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BXT: i915: GPU HANG followed by full crash after suspend #9

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jlaitine opened this issue Jun 15, 2017 · 7 comments
Open

BXT: i915: GPU HANG followed by full crash after suspend #9

jlaitine opened this issue Jun 15, 2017 · 7 comments

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@jlaitine
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jlaitine commented Jun 15, 2017

On joule compute module, soon after doing
echo freeze > /sys/power/state
the device will crash after it wakes up from suspend.

The kernel version is 4.9.27-intel-pk-standard
The xf86-video-intel version is xf86-video-intel/2_2.99.917

This is the crash dump:

[   84.844432] [drm] GPU HANG: ecode 9:0:0xfffffffe, reason: Hang on render ring, action: reset
[   84.853874] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[   84.864454] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[   84.874444] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[   84.885309] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[   84.895397] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[   84.902889] drm/i915: Resetting chip after gpu hang
[   84.910547] BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
[   84.919385] IP: [<ffffffffa022e4c2>] reset_common_ring+0xa2/0x130 [i915]
[   84.926941] PGD 0 [   84.928998] 
[   84.930670] Oops: 0000 [#1] PREEMPT SMP
[   84.934971] Modules linked in: intel_ipu4_isys_mod_bxtB0(O) videobuf2_v4l2 videobuf2_core intel_ipu4_psys_mod_bxtB0(O) int
el_ipu4_mmu_bxtB0(O) intel_ipu4_mod_bxtB0(O) iova intel_ipu4_acpi(O) videobuf2_dma_contig videobuf2_memops videobuf_core dw97
14(O) crlmodule(O) v4l2_common videodev media rfcomm usb_f_mtp usb_f_ecm u_ether usb_f_acm u_serial libcomposite configfs snd
_soc_wm8998 extcon_arizona snd_soc_arizona arizona_micsupp extcon_core snd_soc_core snd_compress ac97_bus arizona_ldo1 gpio_a
rizona iptable_nat nf_nat_ipv4 nf_nat bnep iptable_mangle snd_hda_codec_hdmi mei_spd gpio_keys intel_rapl x86_pkg_temp_therma
l intel_powerclamp coretemp efivars clk_wcove typec_wcove arc4 gpio_wcove iwlmvm(O) mac80211(O) pwm_lpss_pci pwm_lpss btusb b
trtl btbcm iwlwifi(O) spi_pxa2xx_platform snd_hda_intel cfg80211(O) snd_hda_codec snd_hda_core compat(O) snd_pcm i915 fdp_i2c
 fdp i2c_designware_platform i2c_designware_core nci mei_me snd_timer processor_thermal_device dwc3_pci nfc mei intel_soc_dts
_iosf at24 bq25890_charger atmel_mxt_ts nvmem_core hci_uart btintel int3400_thermal acpi_thermal_rel video int3403_thermal in
t340x_thermal_zone soc_button_array nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables nf_conntrack_ipv4 nf_defrag_i
pv4 xt_tcpudp xt_conntrack nf_conntrack iptable_filter ip_tables x_tables uio arizona_i2c 5xx_comms_leds(O)
[   85.068404] CPU: 0 PID: 472 Comm: kworker/0:2 Tainted: G           O    4.9.27-intel-pk-standard #1
[   85.078561] Hardware name: Intel Corp. 570x DVT2/SDS, BIOS GTPP1H3A.X64.0143.B30.1706022158 06/02/2017
[   85.089030] Workqueue: events_long i915_hangcheck_elapsed [i915]
[   85.095779] task: ffff880179cba340 task.stack: ffffc900007f8000
[   85.102424] RIP: 0010:[<ffffffffa022e4c2>]  [<ffffffffa022e4c2>] reset_common_ring+0xa2/0x130 [i915]
[   85.112706] RSP: 0018:ffffc900007fbb30  EFLAGS: 00010246
[   85.118668] RAX: 0000000000000000 RBX: ffff88016aaa8500 RCX: 0000000080000006
[   85.126674] RDX: 0000000000003fd8 RSI: ffff880178d06000 RDI: ffff88017a3a0200
[   85.134681] RBP: ffffc900007fbb48 R08: 0000000000000017 R09: ffffc90010001000
[   85.142692] R10: 0000000000000000 R11: ffff88017b161800 R12: ffff880179c9a000
[   85.150704] R13: 0000000000000000 R14: ffffffff819130f0 R15: ffff880179c9a000
[   85.158718] FS:  0000000000000000(0000) GS:ffff88017fc00000(0000) knlGS:0000000000000000
[   85.167805] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   85.174274] CR2: 0000000000000070 CR3: 0000000002e07000 CR4: 00000000003406f0
[   85.182303] Stack:
[   85.184555]  ffff880178932800 ffff880179ac27d8 ffff88016aaa8500 ffffc900007fbbc0
[   85.192887]  ffffffffa021a9b8 ffff880179ac06e8 0000000000000286 0000000000000286
[   85.201219]  ffffffffa0238a78 ffff880179ac0000 0000000000000000 ffff880179ac0000
[   85.209551] Call Trace:
[   85.212311]  [<ffffffffa021a9b8>] i915_gem_reset+0x148/0x3b0 [i915]
[   85.219364]  [<ffffffffa0238a78>] ? intel_uncore_forcewake_put+0x48/0x60 [i915]
[   85.227575]  [<ffffffff819130f0>] ? bit_wait_io_timeout+0x70/0x70
[   85.234425]  [<ffffffffa01dd29c>] i915_reset+0xdc/0x170 [i915]
[   85.240978]  [<ffffffffa01e274d>] i915_reset_and_wakeup+0x13d/0x150 [i915]
[   85.248711]  [<ffffffffa01e63b6>] i915_handle_error+0x206/0x220 [i915]
[   85.256042]  [<ffffffff8140878d>] ? scnprintf+0x3d/0x70
[   85.261923]  [<ffffffffa022ca0c>] hangcheck_declare_hang+0xcc/0xe0 [i915]
[   85.269562]  [<ffffffffa022bf64>] ? intel_engine_get_active_head+0xb4/0xe0 [i915]
[   85.277982]  [<ffffffffa022cca9>] i915_hangcheck_elapsed+0x289/0x2b0 [i915]
[   85.285800]  [<ffffffff81094dce>] process_one_work+0x1de/0x4c0
[   85.292348]  [<ffffffff810950f8>] worker_thread+0x48/0x4e0
[   85.298506]  [<ffffffff810950b0>] ? process_one_work+0x4c0/0x4c0
[   85.305270]  [<ffffffff8109a257>] kthread+0xd7/0xf0
[   85.310745]  [<ffffffff8109a180>] ? kthread_park+0x60/0x60
[   85.316905]  [<ffffffff81917652>] ret_from_fork+0x22/0x30
[   85.322965] Code: 8b 83 80 00 00 00 c7 40 3c ff ff ff ff 48 8b bb 80 00 00 00 e8 80 36 00 00 8b 05 0a 55 0b 00 85 c0 75 71
 4d 8b ac 24 58 02 00 00 <49> 8b 45 70 48 39 43 70 74 50 4d 85 ed 74 13 48 c7 c0 a0 81 58 
[   85.344442] RIP  [<ffffffffa022e4c2>] reset_common_ring+0xa2/0x130 [i915]
[   85.352081]  RSP <ffffc900007fbb30>
[   85.355984] CR2: 0000000000000070
[   85.373716] ---[ end trace d4d4d62e81cbe6bc ]---
[   85.382625] BUG: unable to handle kernel paging request at ffffffffffffffd8
[   85.390467] IP: [<ffffffff8109acb1>] kthread_data+0x11/0x20
[   85.396736] PGD 2e08067 [   85.399378] PUD 2e0a067 
PMD 0 [   85.402813] 
[   85.404484] Oops: 0000 [#2] PREEMPT SMP
[   85.408786] Modules linked in: intel_ipu4_isys_mod_bxtB0(O) videobuf2_v4l2 videobuf2_core intel_ipu4_psys_mod_bxtB0(O) int
el_ipu4_mmu_bxtB0(O) intel_ipu4_mod_bxtB0(O) iova intel_ipu4_acpi(O) videobuf2_dma_contig videobuf2_memops videobuf_core dw97
14(O) crlmodule(O) v4l2_common videodev media rfcomm usb_f_mtp usb_f_ecm u_ether usb_f_acm u_serial libcomposite configfs snd
_soc_wm8998 extcon_arizona snd_soc_arizona arizona_micsupp extcon_core snd_soc_core snd_compress ac97_bus arizona_ldo1 gpio_a
rizona iptable_nat nf_nat_ipv4 nf_nat bnep iptable_mangle snd_hda_codec_hdmi mei_spd gpio_keys intel_rapl x86_pkg_temp_therma
l intel_powerclamp coretemp efivars clk_wcove typec_wcove arc4 gpio_wcove iwlmvm(O) mac80211(O) pwm_lpss_pci pwm_lpss btusb b
trtl btbcm iwlwifi(O) spi_pxa2xx_platform snd_hda_intel cfg80211(O) snd_hda_codec snd_hda_core compat(O) snd_pcm i915 fdp_i2c
 fdp i2c_designware_platform i2c_designware_core nci mei_me snd_timer processor_thermal_device dwc3_pci nfc mei intel_soc_dts
_iosf at24 bq25890_charger atmel_mxt_ts nvmem_core hci_uart btintel int3400_thermal acpi_thermal_rel video int3403_thermal in
t340x_thermal_zone soc_button_array nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables nf_conntrack_ipv4 nf_defrag_i
pv4 xt_tcpudp xt_conntrack nf_conntrack iptable_filter ip_tables x_tables uio arizona_i2c 5xx_comms_leds(O)
[   85.542261] CPU: 0 PID: 472 Comm: kworker/0:2 Tainted: G      D    O    4.9.27-intel-pk-standard #1
[   85.552419] Hardware name: Intel Corp. 570x DVT2/SDS, BIOS GTPP1H3A.X64.0143.B30.1706022158 06/02/2017
[   85.562877] task: ffff880179cba340 task.stack: ffffc900007f8000
[   85.569521] RIP: 0010:[<ffffffff8109acb1>]  [<ffffffff8109acb1>] kthread_data+0x11/0x20
[   85.578514] RSP: 0018:ffffc900007fbe68  EFLAGS: 00010002
[   85.584474] RAX: 0000000000000000 RBX: ffff88017fc17500 RCX: 0000000000000000
[   85.592483] RDX: ffff88017b005000 RSI: ffff880179cba3c0 RDI: ffff880179cba340
[   85.600492] RBP: ffffc900007fbe70 R08: 0000000000000000 R09: 0000000000000000
[   85.608501] R10: 0000000000000000 R11: ffff880179cba3c0 R12: ffff880179cba340
[   85.616501] R13: 0000000000000000 R14: ffff880179cba808 R15: 0000000000017500
[   85.624511] FS:  0000000000000000(0000) GS:ffff88017fc00000(0000) knlGS:0000000000000000
[   85.633595] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   85.640044] CR2: 0000000000000028 CR3: 000000017abd3000 CR4: 00000000003406f0
[   85.648054] Stack:
[   85.650306]  ffffffff8109602e ffffc900007fbec8 ffffffff819125be ffffc900007fbee0
[   85.658651]  ffffffff8107ead6 0000000000000000 0000000000000000 ffff880179cba340
[   85.666993]  ffffc900007fbf10 ffffc900007fbb20 0000000000000000 0000000000000009
[   85.675334] Call Trace:
[   85.678075]  [<ffffffff8109602e>] ? wq_worker_sleeping+0xe/0x80
[   85.684721]  [<ffffffff819125be>] __schedule+0x35e/0x5a0
[   85.690683]  [<ffffffff8107ead6>] ? release_task+0x2d6/0x3c0
[   85.697035]  [<ffffffff810a59e8>] do_task_dead+0x38/0x40
[   85.702996]  [<ffffffff8108033f>] do_exit+0x79f/0xb00
[   85.708657]  [<ffffffff819187d7>] rewind_stack_do_exit+0x17/0x20
[   85.715400] Code: 80 04 00 00 48 c7 c7 a8 7d bc 81 e8 7a 0f fe ff eb ca 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8b 87 68
 04 00 00 55 48 89 e5 5d <48> 8b 40 d8 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 
[   85.737001] RIP  [<ffffffff8109acb1>] kthread_data+0x11/0x20
[   85.743361]  RSP <ffffc900007fbe68>
[   85.747292] CR2: ffffffffffffffd8
[   85.751010] ---[ end trace d4d4d62e81cbe6bd ]---
[   85.756160] Fixing recursive fault but reboot is needed!
[   85.762094] BUG: scheduling while atomic: kworker/0:2/472/0x00000003
[   85.769194] Modules linked in: intel_ipu4_isys_mod_bxtB0(O) videobuf2_v4l2 videobuf2_core intel_ipu4_psys_mod_bxtB0(O) int
el_ipu4_mmu_bxtB0(O) intel_ipu4_mod_bxtB0(O) iova intel_ipu4_acpi(O) videobuf2_dma_contig videobuf2_memops videobuf_core dw97
14(O) crlmodule(O) v4l2_common videodev media rfcomm usb_f_mtp usb_f_ecm u_ether usb_f_acm u_serial libcomposite configfs snd
_soc_wm8998 extcon_arizona snd_soc_arizona arizona_micsupp extcon_core snd_soc_core snd_compress ac97_bus arizona_ldo1 gpio_a
rizona iptable_nat nf_nat_ipv4 nf_nat bnep iptable_mangle snd_hda_codec_hdmi mei_spd gpio_keys intel_rapl x86_pkg_temp_therma
l intel_powerclamp coretemp efivars clk_wcove typec_wcove arc4 gpio_wcove iwlmvm(O) mac80211(O) pwm_lpss_pci pwm_lpss btusb b
trtl btbcm iwlwifi(O) spi_pxa2xx_platform snd_hda_intel cfg80211(O) snd_hda_codec snd_hda_core compat(O) snd_pcm i915 fdp_i2c
 fdp i2c_designware_platform i2c_designware_core nci mei_me snd_timer processor_thermal_device dwc3_pci nfc mei intel_soc_dts
_iosf at24 bq25890_charger atmel_mxt_ts nvmem_core hci_uart btintel int3400_thermal acpi_thermal_rel video int3403_thermal in
t340x_thermal_zone soc_button_array nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables nf_conntrack_ipv4 nf_defrag_i
pv4 xt_tcpudp xt_conntrack nf_conntrack iptable_filter ip_tables x_tables uio arizona_i2c 5xx_comms_leds(O)
[   85.901747] CPU: 0 PID: 472 Comm: kworker/0:2 Tainted: G      D    O    4.9.27-intel-pk-standard #1
[   85.911860] Hardware name: Intel Corp. 570x DVT2/SDS, BIOS GTPP1H3A.X64.0143.B30.1706022158 06/02/2017
[   85.922271]  ffffc900007fbe60 ffffffff813fc6da ffff88017fc17500 ffff880179cba340
[   85.930552]  ffffc900007fbe70 ffffffff810a0cbf ffffc900007fbec8 ffffffff81912654
[   85.938830]  ffffc900007fbee0 ffffffff81149e01 0000000000000008 ffffc900007fbef0
[   85.947120] Call Trace:
[   85.949851]  [<ffffffff813fc6da>] dump_stack+0x4d/0x63
[   85.955592]  [<ffffffff810a0cbf>] __schedule_bug+0x4f/0x70
[   85.961721]  [<ffffffff81912654>] __schedule+0x3f4/0x5a0
[   85.967657]  [<ffffffff81149e01>] ? printk+0x48/0x50
[   85.973203]  [<ffffffff8191283d>] schedule+0x3d/0x90
[   85.978747]  [<ffffffff810804da>] do_exit+0x93a/0xb00
[   85.984388]  [<ffffffff819187d7>] rewind_stack_do_exit+0x17/0x20
@jlaitine
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Here is some further information:

The crash occurs in intel_lrc.c, static void reset_common_ring(..), in
if (request->ctx != port[0].request->ctx)
as the port[0].request is NULL.

The kernel is using execlists, so otherwise it would have been returned earlier.

If I check the port and port[0].request, I can avoid the kernel crash. Instead I will just get:

[   83.820647] [drm] GPU HANG: ecode 9:0:0xfffffffe, reason: Hang on render ring, action: reset
[   83.830102] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[   83.840417] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[   83.850340] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[   83.861180] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[   83.871216] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[   83.878613] drm/i915: Resetting chip after gpu hang
[   83.894610] [drm] RC6 on
[   95.770226] drm/i915: Resetting chip after gpu hang
[   95.776257] [drm:i915_reset [i915]] *ERROR* GPU recovery failed

@jlaitine
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It also seems that the issue is not re-producible if I have an HDMI display connected to the board. It only crashes if I run it on a console without a display.

@jlaitine
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I am fixing this in ref-os-iot like this:
#11

First there is one patch which removes the crash when using execlists.
Then there are two following patches, cherry-picked from upstream, which just re-enable GuC. Actually these make the first one obsolete, but I still like to have it in case we later revert back to execlists for some reason.

@jlaitine
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I just tested that the GPU HANG itself after suspend can be resolved with the upstream commit bafb2f7d4755bf1571bd5e9a03b97f3fc4fe69ae

Earlier this has been already integrated into the production kernel, but it seems that it has been reverted:

commit 0ee72d8f9b8e17b8e4ccfebc7a25cbc2d395cd6a
Author: Greg Kroah-Hartman <[email protected]>
Date:   Wed Apr 12 15:49:39 2017 +0200

    Revert "drm/i915/execlists: Reset RING registers upon resume"
    
    This reverts commit f2a0409a08502d64fbe3990354dff5902b08d2fb which is
    commit bafb2f7d4755bf1571bd5e9a03b97f3fc4fe69ae upstream.
    
    It was reported to have problems.

I wonder if the problems could be resolved in a way that this could be included back?

@jlaitine
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I am not experiencing any issues with the above, it just fixes the GPU HANG on resume, so I'd suggest integrating it back.

@fei-yang
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A little confused. The revert is in the latest stable update. Are you saying we need to revert the revert?

@jlaitine
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Yes, that's what I suggested. It fixes the GPU HANG on resume on BXT/Joule. I am not aware of why it was reverted in the first place. I have been only testing on BXT, so if someone knows why it was reverted, please comment.

rweight pushed a commit that referenced this issue Jul 11, 2017
|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 1, irqs_disabled(): 0, pid: 3194, name: rpc.nfsd
|Preemption disabled at:[<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
|CPU: 6 PID: 3194 Comm: rpc.nfsd Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409630000 ffff8800d9a33c78 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff8800d9a33c98 ffffffff81073c86 ffff880408dd6008
| ffff880408dd6000 ffff8800d9a33cb8 ffffffff815c3d84 ffff88040b3ac000
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d84>] rt_spin_lock+0x24/0x50
| [<ffffffffa06beec0>] svc_xprt_do_enqueue+0x80/0x230 [sunrpc]
| [<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
| [<ffffffffa06c03ed>] svc_add_new_perm_xprt+0x6d/0x80 [sunrpc]
| [<ffffffffa06b2693>] svc_addsock+0x143/0x200 [sunrpc]
| [<ffffffffa072e69c>] write_ports+0x28c/0x340 [nfsd]
| [<ffffffffa072d2ac>] nfsctl_transaction_write+0x4c/0x80 [nfsd]
| [<ffffffff8117ee83>] vfs_write+0xb3/0x1d0
| [<ffffffff8117f889>] SyS_write+0x49/0xb0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
rweight pushed a commit that referenced this issue Jul 11, 2017
Locking functions previously using read_lock_irq()/read_lock_irqsave() were
changed to local_irq_disable/save(), leading to gripes.  Use nort variants.

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 0, irqs_disabled(): 1, pid: 5947, name: alsa-sink-ALC88
|CPU: 5 PID: 5947 Comm: alsa-sink-ALC88 Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409316240 ffff88040866fa38 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff88040866fa58 ffffffff81073c86 ffffffffa03b2640
| ffff88040239ec00 ffff88040866fa78 ffffffff815c3d34 ffffffffa03b2640
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d34>] __rt_spin_lock+0x24/0x50
| [<ffffffff815c4044>] rt_read_lock+0x34/0x40
| [<ffffffffa03a2979>] snd_pcm_stream_lock+0x29/0x70 [snd_pcm]
| [<ffffffffa03a355d>] snd_pcm_playback_poll+0x5d/0x120 [snd_pcm]
| [<ffffffff811937a2>] do_sys_poll+0x322/0x5b0
| [<ffffffff81193d48>] SyS_ppoll+0x1a8/0x1c0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
rweight pushed a commit that referenced this issue Aug 15, 2017
[ Upstream commit b4846fc3c8559649277e3e4e6b5cec5348a8d208 ]

Andrey reported a lockdep warning on non-initialized
spinlock:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.
 CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  __dump_stack lib/dump_stack.c:16
  dump_stack+0x292/0x395 lib/dump_stack.c:52
  register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755
  ? 0xffffffffa0000000
  __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255
  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
  __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135
  _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh ./include/linux/spinlock.h:304
  ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076
  igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194
  ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736

We miss a spin_lock_init() in igmpv3_add_delrec(), probably
because previously we never use it on this code path. Since
we already unlink it from the global mc_tomb list, it is
probably safe not to acquire this spinlock here. It does not
harm to have it although, to avoid conditional locking.

Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()")
Reported-by: Andrey Konovalov <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rweight pushed a commit that referenced this issue Aug 15, 2017
commit cdea46566bb21ce309725a024208322a409055cc upstream.

A vendor with a system having more than 128 CPUs occasionally encounters
the following crash during shutdown. This is not an easily reproduceable
event, but the vendor was able to provide the following analysis of the
crash, which exhibits the same footprint each time.

crash> bt
PID: 0      TASK: ffff88017c70ce70  CPU: 5   COMMAND: "swapper/5"
 #0 [ffff88085c143ac8] machine_kexec at ffffffff81059c8b
 #1 [ffff88085c143b28] __crash_kexec at ffffffff811052e2
 #2 [ffff88085c143bf8] crash_kexec at ffffffff811053d0
 #3 [ffff88085c143c10] oops_end at ffffffff8168ef88
 #4 [ffff88085c143c38] no_context at ffffffff8167ebb3
 #5 [ffff88085c143c88] __bad_area_nosemaphore at ffffffff8167ec49
 #6 [ffff88085c143cd0] bad_area_nosemaphore at ffffffff8167edb3
 #7 [ffff88085c143ce0] __do_page_fault at ffffffff81691d1e
 #8 [ffff88085c143d40] do_page_fault at ffffffff81691ec5
 #9 [ffff88085c143d70] page_fault at ffffffff8168e188
    [exception RIP: unknown or invalid address]
    RIP: ffffffffa053c800  RSP: ffff88085c143e28  RFLAGS: 00010206
    RAX: ffff88017c72bfd8  RBX: ffff88017a8dc000  RCX: ffff8810588b5ac8
    RDX: ffff8810588b5a00  RSI: ffffffffa053c800  RDI: ffff8810588b5a00
    RBP: ffff88085c143e58   R8: ffff88017c70d408   R9: ffff88017a8dc000
    R10: 0000000000000002  R11: ffff88085c143da0  R12: ffff8810588b5ac8
    R13: 0000000000000100  R14: ffffffffa053c800  R15: ffff8810588b5a00
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
    <IRQ stack>
    [exception RIP: cpuidle_enter_state+82]
    RIP: ffffffff81514192  RSP: ffff88017c72be50  RFLAGS: 00000202
    RAX: 0000001e4c3c6f16  RBX: 000000000000f8a0  RCX: 0000000000000018
    RDX: 0000000225c17d03  RSI: ffff88017c72bfd8  RDI: 0000001e4c3c6f16
    RBP: ffff88017c72be78   R8: 000000000000237e   R9: 0000000000000018
    R10: 0000000000002494  R11: 0000000000000001  R12: ffff88017c72be20
    R13: ffff88085c14f8e0  R14: 0000000000000082  R15: 0000001e4c3bb400
    ORIG_RAX: ffffffffffffff10  CS: 0010  SS: 0018

This is the corresponding stack trace

It has crashed because the area pointed with RIP extracted from timer
element is already removed during a shutdown process.

The function is smi_timeout().

And we think ffff8810588b5a00 in RDX is a parameter struct smi_info

crash> rd ffff8810588b5a00 20
ffff8810588b5a00:  ffff8810588b6000 0000000000000000   .`.X............
ffff8810588b5a10:  ffff880853264400 ffffffffa05417e0   .D&S......T.....
ffff8810588b5a20:  24a024a000000000 0000000000000000   .....$.$........
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a40:  ffffffffa053a040 ffffffffa053a060   @.S.....`.S.....
ffff8810588b5a50:  0000000000000000 0000000100000001   ................
ffff8810588b5a60:  0000000000000000 0000000000000e00   ................
ffff8810588b5a70:  ffffffffa053a580 ffffffffa053a6e0   ..S.......S.....
ffff8810588b5a80:  ffffffffa053a4a0 ffffffffa053a250   ..S.....P.S.....
ffff8810588b5a90:  0000000500000002 0000000000000000   ................

Unfortunately the top of this area is already detroyed by someone.
But because of two reasonns we think this is struct smi_info
 1) The address included in between  ffff8810588b5a70 and ffff8810588b5a80:
  are inside of ipmi_si_intf.c  see crash> module ffff88085779d2c0

 2) We've found the area which point this.
  It is offset 0x68 of  ffff880859df4000

crash> rd  ffff880859df4000 100
ffff880859df4000:  0000000000000000 0000000000000001   ................
ffff880859df4010:  ffffffffa0535290 dead000000000200   .RS.............
ffff880859df4020:  ffff880859df4020 ffff880859df4020    @.Y.... @.Y....
ffff880859df4030:  0000000000000002 0000000000100010   ................
ffff880859df4040:  ffff880859df4040 ffff880859df4040   @@.Y....@@.Y....
ffff880859df4050:  0000000000000000 0000000000000000   ................
ffff880859df4060:  0000000000000000 ffff8810588b5a00   .........Z.X....
ffff880859df4070:  0000000000000001 ffff880859df4078   [email protected]....

 If we regards it as struct ipmi_smi in shutdown process
 it looks consistent.

The remedy for this apparent race is affixed below.

Signed-off-by: Tony Camuso <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

This was first introduced in 7ea0ed2 ipmi: Make the
message handler easier to use for SMI interfaces
where some code was moved outside of the rcu_read_lock()
and the lock was not added.

Signed-off-by: Corey Minyard <[email protected]>
rweight pushed a commit that referenced this issue Aug 15, 2017
|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 1, irqs_disabled(): 0, pid: 3194, name: rpc.nfsd
|Preemption disabled at:[<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
|CPU: 6 PID: 3194 Comm: rpc.nfsd Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409630000 ffff8800d9a33c78 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff8800d9a33c98 ffffffff81073c86 ffff880408dd6008
| ffff880408dd6000 ffff8800d9a33cb8 ffffffff815c3d84 ffff88040b3ac000
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d84>] rt_spin_lock+0x24/0x50
| [<ffffffffa06beec0>] svc_xprt_do_enqueue+0x80/0x230 [sunrpc]
| [<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
| [<ffffffffa06c03ed>] svc_add_new_perm_xprt+0x6d/0x80 [sunrpc]
| [<ffffffffa06b2693>] svc_addsock+0x143/0x200 [sunrpc]
| [<ffffffffa072e69c>] write_ports+0x28c/0x340 [nfsd]
| [<ffffffffa072d2ac>] nfsctl_transaction_write+0x4c/0x80 [nfsd]
| [<ffffffff8117ee83>] vfs_write+0xb3/0x1d0
| [<ffffffff8117f889>] SyS_write+0x49/0xb0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
rweight pushed a commit that referenced this issue Aug 15, 2017
Locking functions previously using read_lock_irq()/read_lock_irqsave() were
changed to local_irq_disable/save(), leading to gripes.  Use nort variants.

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 0, irqs_disabled(): 1, pid: 5947, name: alsa-sink-ALC88
|CPU: 5 PID: 5947 Comm: alsa-sink-ALC88 Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409316240 ffff88040866fa38 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff88040866fa58 ffffffff81073c86 ffffffffa03b2640
| ffff88040239ec00 ffff88040866fa78 ffffffff815c3d34 ffffffffa03b2640
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d34>] __rt_spin_lock+0x24/0x50
| [<ffffffff815c4044>] rt_read_lock+0x34/0x40
| [<ffffffffa03a2979>] snd_pcm_stream_lock+0x29/0x70 [snd_pcm]
| [<ffffffffa03a355d>] snd_pcm_playback_poll+0x5d/0x120 [snd_pcm]
| [<ffffffff811937a2>] do_sys_poll+0x322/0x5b0
| [<ffffffff81193d48>] SyS_ppoll+0x1a8/0x1c0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
sys-oak pushed a commit that referenced this issue Sep 7, 2017
|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 1, irqs_disabled(): 0, pid: 3194, name: rpc.nfsd
|Preemption disabled at:[<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
|CPU: 6 PID: 3194 Comm: rpc.nfsd Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409630000 ffff8800d9a33c78 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff8800d9a33c98 ffffffff81073c86 ffff880408dd6008
| ffff880408dd6000 ffff8800d9a33cb8 ffffffff815c3d84 ffff88040b3ac000
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d84>] rt_spin_lock+0x24/0x50
| [<ffffffffa06beec0>] svc_xprt_do_enqueue+0x80/0x230 [sunrpc]
| [<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
| [<ffffffffa06c03ed>] svc_add_new_perm_xprt+0x6d/0x80 [sunrpc]
| [<ffffffffa06b2693>] svc_addsock+0x143/0x200 [sunrpc]
| [<ffffffffa072e69c>] write_ports+0x28c/0x340 [nfsd]
| [<ffffffffa072d2ac>] nfsctl_transaction_write+0x4c/0x80 [nfsd]
| [<ffffffff8117ee83>] vfs_write+0xb3/0x1d0
| [<ffffffff8117f889>] SyS_write+0x49/0xb0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
sys-oak pushed a commit that referenced this issue Sep 7, 2017
Locking functions previously using read_lock_irq()/read_lock_irqsave() were
changed to local_irq_disable/save(), leading to gripes.  Use nort variants.

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 0, irqs_disabled(): 1, pid: 5947, name: alsa-sink-ALC88
|CPU: 5 PID: 5947 Comm: alsa-sink-ALC88 Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409316240 ffff88040866fa38 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff88040866fa58 ffffffff81073c86 ffffffffa03b2640
| ffff88040239ec00 ffff88040866fa78 ffffffff815c3d34 ffffffffa03b2640
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d34>] __rt_spin_lock+0x24/0x50
| [<ffffffff815c4044>] rt_read_lock+0x34/0x40
| [<ffffffffa03a2979>] snd_pcm_stream_lock+0x29/0x70 [snd_pcm]
| [<ffffffffa03a355d>] snd_pcm_playback_poll+0x5d/0x120 [snd_pcm]
| [<ffffffff811937a2>] do_sys_poll+0x322/0x5b0
| [<ffffffff81193d48>] SyS_ppoll+0x1a8/0x1c0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
sys-oak pushed a commit that referenced this issue Nov 21, 2017
commit ab219221a5064abfff9f78c323c4a257b16cdb81 upstream.

The dummy-hcd driver calls the gadget driver's disconnect callback
under the wrong conditions.  It should invoke the callback when Vbus
power is turned off, but instead it does so when the D+ pullup is
turned off.

This can cause a deadlock in the composite core when a gadget driver
is unregistered:

[   88.361471] ============================================
[   88.362014] WARNING: possible recursive locking detected
[   88.362580] 4.14.0-rc2+ #9 Not tainted
[   88.363010] --------------------------------------------
[   88.363561] v4l_id/526 is trying to acquire lock:
[   88.364062]  (&(&cdev->lock)->rlock){....}, at: [<ffffffffa0547e03>] composite_disconnect+0x43/0x100 [libcomposite]
[   88.365051]
[   88.365051] but task is already holding lock:
[   88.365826]  (&(&cdev->lock)->rlock){....}, at: [<ffffffffa0547b09>] usb_function_deactivate+0x29/0x80 [libcomposite]
[   88.366858]
[   88.366858] other info that might help us debug this:
[   88.368301]  Possible unsafe locking scenario:
[   88.368301]
[   88.369304]        CPU0
[   88.369701]        ----
[   88.370101]   lock(&(&cdev->lock)->rlock);
[   88.370623]   lock(&(&cdev->lock)->rlock);
[   88.371145]
[   88.371145]  *** DEADLOCK ***
[   88.371145]
[   88.372211]  May be due to missing lock nesting notation
[   88.372211]
[   88.373191] 2 locks held by v4l_id/526:
[   88.373715]  #0:  (&(&cdev->lock)->rlock){....}, at: [<ffffffffa0547b09>] usb_function_deactivate+0x29/0x80 [libcomposite]
[   88.374814]  #1:  (&(&dum_hcd->dum->lock)->rlock){....}, at: [<ffffffffa05bd48d>] dummy_pullup+0x7d/0xf0 [dummy_hcd]
[   88.376289]
[   88.376289] stack backtrace:
[   88.377726] CPU: 0 PID: 526 Comm: v4l_id Not tainted 4.14.0-rc2+ #9
[   88.378557] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   88.379504] Call Trace:
[   88.380019]  dump_stack+0x86/0xc7
[   88.380605]  __lock_acquire+0x841/0x1120
[   88.381252]  lock_acquire+0xd5/0x1c0
[   88.381865]  ? composite_disconnect+0x43/0x100 [libcomposite]
[   88.382668]  _raw_spin_lock_irqsave+0x40/0x54
[   88.383357]  ? composite_disconnect+0x43/0x100 [libcomposite]
[   88.384290]  composite_disconnect+0x43/0x100 [libcomposite]
[   88.385490]  set_link_state+0x2d4/0x3c0 [dummy_hcd]
[   88.386436]  dummy_pullup+0xa7/0xf0 [dummy_hcd]
[   88.387195]  usb_gadget_disconnect+0xd8/0x160 [udc_core]
[   88.387990]  usb_gadget_deactivate+0xd3/0x160 [udc_core]
[   88.388793]  usb_function_deactivate+0x64/0x80 [libcomposite]
[   88.389628]  uvc_function_disconnect+0x1e/0x40 [usb_f_uvc]

This patch changes the code to test the port-power status bit rather
than the port-connect status bit when deciding whether to isue the
callback.

Signed-off-by: Alan Stern <[email protected]>
Reported-by: David Tulloh <[email protected]>
Signed-off-by: Felipe Balbi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Jan 11, 2018
[ Upstream commit ec4fbd64751de18729eaa816ec69e4b504b5a7a2 ]

Dmitry reported a lockdep splat [1] (false positive) that we can fix
by releasing the spinlock before calling icmp_send() from ip_expire()

This is a false positive because sending an ICMP message can not
possibly re-enter the IP frag engine.

[1]
[ INFO: possible circular locking dependency detected ]
4.10.0+ #29 Not tainted
-------------------------------------------------------
modprobe/12392 is trying to acquire lock:
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] spin_lock
include/linux/spinlock.h:299 [inline]
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] __netif_tx_lock
include/linux/netdevice.h:3486 [inline]
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>]
sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180

but task is already holding lock:
 (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
 (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&q->lock)->rlock){+.-...}:
       validate_chain kernel/locking/lockdep.c:2267 [inline]
       __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
       lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
       spin_lock include/linux/spinlock.h:299 [inline]
       ip_defrag+0x3a2/0x4130 net/ipv4/ip_fragment.c:669
       ip_check_defrag+0x4e3/0x8b0 net/ipv4/ip_fragment.c:713
       packet_rcv_fanout+0x282/0x800 net/packet/af_packet.c:1459
       deliver_skb net/core/dev.c:1834 [inline]
       dev_queue_xmit_nit+0x294/0xa90 net/core/dev.c:1890
       xmit_one net/core/dev.c:2903 [inline]
       dev_hard_start_xmit+0x16b/0xab0 net/core/dev.c:2923
       sch_direct_xmit+0x31f/0x6d0 net/sched/sch_generic.c:182
       __dev_xmit_skb net/core/dev.c:3092 [inline]
       __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
       dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
       neigh_resolve_output+0x6b9/0xb10 net/core/neighbour.c:1308
       neigh_output include/net/neighbour.h:478 [inline]
       ip_finish_output2+0x8b8/0x15a0 net/ipv4/ip_output.c:228
       ip_do_fragment+0x1d93/0x2720 net/ipv4/ip_output.c:672
       ip_fragment.constprop.54+0x145/0x200 net/ipv4/ip_output.c:545
       ip_finish_output+0x82d/0xe10 net/ipv4/ip_output.c:314
       NF_HOOK_COND include/linux/netfilter.h:246 [inline]
       ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
       dst_output include/net/dst.h:486 [inline]
       ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
       ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
       ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
       raw_sendmsg+0x26de/0x3a00 net/ipv4/raw.c:655
       inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
       sock_sendmsg_nosec net/socket.c:633 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:643
       ___sys_sendmsg+0x4a3/0x9f0 net/socket.c:1985
       __sys_sendmmsg+0x25c/0x750 net/socket.c:2075
       SYSC_sendmmsg net/socket.c:2106 [inline]
       SyS_sendmmsg+0x35/0x60 net/socket.c:2101
       do_syscall_64+0x2e8/0x930 arch/x86/entry/common.c:281
       return_from_SYSCALL_64+0x0/0x7a

-> #0 (_xmit_ETHER#2){+.-...}:
       check_prev_add kernel/locking/lockdep.c:1830 [inline]
       check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940
       validate_chain kernel/locking/lockdep.c:2267 [inline]
       __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
       lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
       spin_lock include/linux/spinlock.h:299 [inline]
       __netif_tx_lock include/linux/netdevice.h:3486 [inline]
       sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180
       __dev_xmit_skb net/core/dev.c:3092 [inline]
       __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
       dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
       neigh_hh_output include/net/neighbour.h:468 [inline]
       neigh_output include/net/neighbour.h:476 [inline]
       ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228
       ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316
       NF_HOOK_COND include/linux/netfilter.h:246 [inline]
       ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
       dst_output include/net/dst.h:486 [inline]
       ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
       ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
       ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
       icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394
       icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754
       ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239
       call_timer_fn+0x241/0x820 kernel/time/timer.c:1268
       expire_timers kernel/time/timer.c:1307 [inline]
       __run_timers+0x960/0xcf0 kernel/time/timer.c:1601
       run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
       __do_softirq+0x31f/0xbe7 kernel/softirq.c:284
       invoke_softirq kernel/softirq.c:364 [inline]
       irq_exit+0x1cc/0x200 kernel/softirq.c:405
       exiting_irq arch/x86/include/asm/apic.h:657 [inline]
       smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962
       apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707
       __read_once_size include/linux/compiler.h:254 [inline]
       atomic_read arch/x86/include/asm/atomic.h:26 [inline]
       rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline]
       __rcu_is_watching kernel/rcu/tree.c:1133 [inline]
       rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147
       rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293
       radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
       filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335
       do_fault_around mm/memory.c:3231 [inline]
       do_read_fault mm/memory.c:3265 [inline]
       do_fault+0xbd5/0x2080 mm/memory.c:3370
       handle_pte_fault mm/memory.c:3600 [inline]
       __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714
       handle_mm_fault+0x1e2/0x480 mm/memory.c:3751
       __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397
       do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460
       page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&q->lock)->rlock);
                               lock(_xmit_ETHER#2);
                               lock(&(&q->lock)->rlock);
  lock(_xmit_ETHER#2);

 *** DEADLOCK ***

10 locks held by modprobe/12392:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff81329758>]
__do_page_fault+0x2b8/0xb60 arch/x86/mm/fault.c:1336
 #1:  (rcu_read_lock){......}, at: [<ffffffff8188cab6>]
filemap_map_pages+0x1e6/0x1570 mm/filemap.c:2324
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
spin_lock include/linux/spinlock.h:299 [inline]
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
pte_alloc_one_map mm/memory.c:2944 [inline]
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
alloc_set_pte+0x13b8/0x1b90 mm/memory.c:3072
 #3:  (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
lockdep_copy_map include/linux/lockdep.h:175 [inline]
 #3:  (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
call_timer_fn+0x1c2/0x820 kernel/time/timer.c:1258
 #4:  (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
 #4:  (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201
 #5:  (rcu_read_lock){......}, at: [<ffffffff8389a633>]
ip_expire+0x1b3/0x6c0 net/ipv4/ip_fragment.c:216
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] spin_trylock
include/linux/spinlock.h:309 [inline]
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] icmp_xmit_lock
net/ipv4/icmp.c:219 [inline]
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>]
icmp_send+0x803/0x1c80 net/ipv4/icmp.c:681
 #7:  (rcu_read_lock_bh){......}, at: [<ffffffff838ab9a1>]
ip_finish_output2+0x2c1/0x15a0 net/ipv4/ip_output.c:198
 #8:  (rcu_read_lock_bh){......}, at: [<ffffffff836d1dee>]
__dev_queue_xmit+0x23e/0x1e60 net/core/dev.c:3324
 #9:  (dev->qdisc_running_key ?: &qdisc_running_key){+.....}, at:
[<ffffffff836d3a27>] dev_queue_xmit+0x17/0x20 net/core/dev.c:3423

stack backtrace:
CPU: 0 PID: 12392 Comm: modprobe Not tainted 4.10.0+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x2ee/0x3ef lib/dump_stack.c:52
 print_circular_bug+0x307/0x3b0 kernel/locking/lockdep.c:1204
 check_prev_add kernel/locking/lockdep.c:1830 [inline]
 check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940
 validate_chain kernel/locking/lockdep.c:2267 [inline]
 __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:299 [inline]
 __netif_tx_lock include/linux/netdevice.h:3486 [inline]
 sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180
 __dev_xmit_skb net/core/dev.c:3092 [inline]
 __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
 neigh_hh_output include/net/neighbour.h:468 [inline]
 neigh_output include/net/neighbour.h:476 [inline]
 ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228
 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:246 [inline]
 ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
 dst_output include/net/dst.h:486 [inline]
 ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394
 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754
 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239
 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268
 expire_timers kernel/time/timer.c:1307 [inline]
 __run_timers+0x960/0xcf0 kernel/time/timer.c:1601
 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364 [inline]
 irq_exit+0x1cc/0x200 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:657 [inline]
 smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707
RIP: 0010:__read_once_size include/linux/compiler.h:254 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline]
RIP: 0010:__rcu_is_watching kernel/rcu/tree.c:1133 [inline]
RIP: 0010:rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147
RSP: 0000:ffff8801c391f120 EFLAGS: 00000a03 ORIG_RAX: ffffffffffffff10
RAX: dffffc0000000000 RBX: ffff8801c391f148 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000055edd4374000 RDI: ffff8801dbe1ae0c
RBP: ffff8801c391f1a0 R08: 0000000000000002 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000002 R12: 1ffff10038723e25
R13: ffff8801dbe1ae00 R14: ffff8801c391f680 R15: dffffc0000000000
 </IRQ>
 rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293
 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
 filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335
 do_fault_around mm/memory.c:3231 [inline]
 do_read_fault mm/memory.c:3265 [inline]
 do_fault+0xbd5/0x2080 mm/memory.c:3370
 handle_pte_fault mm/memory.c:3600 [inline]
 __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714
 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751
 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397
 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460
 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011
RIP: 0033:0x7f83172f2786
RSP: 002b:00007fffe859ae80 EFLAGS: 00010293
RAX: 000055edd4373040 RBX: 00007f83175111c8 RCX: 000055edd4373238
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f8317510970
RBP: 00007fffe859afd0 R08: 0000000000000009 R09: 0000000000000000
R10: 0000000000000064 R11: 0000000000000000 R12: 000055edd4373040
R13: 0000000000000000 R14: 00007fffe859afe8 R15: 0000000000000000

Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue May 8, 2018
[ Upstream commit d754941225a7dbc61f6dd2173fa9498049f9a7ee ]

If, for any reason, userland shuts down iscsi transport interfaces
before proper logouts - like when logging in to LUNs manually, without
logging out on server shutdown, or when automated scripts can't
umount/logout from logged LUNs - kernel will hang forever on its
sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all
still existent paths.

PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow"
 #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee
 #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5
 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199
 #3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604
 #4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c
 #5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10
 #6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7
 #7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe
 #8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7
 #9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c

This happens because iscsi_eh_cmd_timed_out(), the transport layer
timeout helper, would tell the queue timeout function (scsi_times_out)
to reset the request timer over and over, until the session state is
back to logged in state. Unfortunately, during server shutdown, this
might never happen again.

Other option would be "not to handle" the issue in the transport
layer. That would trigger the error handler logic, which would also need
the session state to be logged in again.

Best option, for such case, is to tell upper layers that the command was
handled during the transport layer error handler helper, marking it as
DID_NO_CONNECT, which will allow completion and inform about the
problem.

After the session was marked as ISCSI_STATE_FAILED, due to the first
timeout during the server shutdown phase, all subsequent cmds will fail
to be queued, allowing upper logic to fail faster.

Signed-off-by: Rafael David Tinoco <[email protected]>
Reviewed-by: Lee Duncan <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue May 24, 2018
…s found

[ Upstream commit 72f17baf2352ded6a1d3f4bb2d15da8c678cd2cb ]

If an OVS_ATTR_NESTED attribute type is found while walking
through netlink attributes, we call nlattr_set() recursively
passing the length table for the following nested attributes, if
different from the current one.

However, once we're done with those sub-nested attributes, we
should continue walking through attributes using the current
table, instead of using the one related to the sub-nested
attributes.

For example, given this sequence:

1  OVS_KEY_ATTR_PRIORITY
2  OVS_KEY_ATTR_TUNNEL
3	OVS_TUNNEL_KEY_ATTR_ID
4	OVS_TUNNEL_KEY_ATTR_IPV4_SRC
5	OVS_TUNNEL_KEY_ATTR_IPV4_DST
6	OVS_TUNNEL_KEY_ATTR_TTL
7	OVS_TUNNEL_KEY_ATTR_TP_SRC
8	OVS_TUNNEL_KEY_ATTR_TP_DST
9  OVS_KEY_ATTR_IN_PORT
10 OVS_KEY_ATTR_SKB_MARK
11 OVS_KEY_ATTR_MPLS

we switch to the 'ovs_tunnel_key_lens' table on attribute #3,
and we don't switch back to 'ovs_key_lens' while setting
attributes #9 to #11 in the sequence. As OVS_KEY_ATTR_MPLS
evaluates to 21, and the array size of 'ovs_tunnel_key_lens' is
15, we also get this kind of KASan splat while accessing the
wrong table:

[ 7654.586496] ==================================================================
[ 7654.594573] BUG: KASAN: global-out-of-bounds in nlattr_set+0x164/0xde9 [openvswitch]
[ 7654.603214] Read of size 4 at addr ffffffffc169ecf0 by task handler29/87430
[ 7654.610983]
[ 7654.612644] CPU: 21 PID: 87430 Comm: handler29 Kdump: loaded Not tainted 3.10.0-866.el7.test.x86_64 #1
[ 7654.623030] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.1.7 06/16/2016
[ 7654.631379] Call Trace:
[ 7654.634108]  [<ffffffffb65a7c50>] dump_stack+0x19/0x1b
[ 7654.639843]  [<ffffffffb53ff373>] print_address_description+0x33/0x290
[ 7654.647129]  [<ffffffffc169b37b>] ? nlattr_set+0x164/0xde9 [openvswitch]
[ 7654.654607]  [<ffffffffb53ff812>] kasan_report.part.3+0x242/0x330
[ 7654.661406]  [<ffffffffb53ff9b4>] __asan_report_load4_noabort+0x34/0x40
[ 7654.668789]  [<ffffffffc169b37b>] nlattr_set+0x164/0xde9 [openvswitch]
[ 7654.676076]  [<ffffffffc167ef68>] ovs_nla_get_match+0x10c8/0x1900 [openvswitch]
[ 7654.684234]  [<ffffffffb61e9cc8>] ? genl_rcv+0x28/0x40
[ 7654.689968]  [<ffffffffb61e7733>] ? netlink_unicast+0x3f3/0x590
[ 7654.696574]  [<ffffffffc167dea0>] ? ovs_nla_put_tunnel_info+0xb0/0xb0 [openvswitch]
[ 7654.705122]  [<ffffffffb4f41b50>] ? unwind_get_return_address+0xb0/0xb0
[ 7654.712503]  [<ffffffffb65d9355>] ? system_call_fastpath+0x1c/0x21
[ 7654.719401]  [<ffffffffb4f41d79>] ? update_stack_state+0x229/0x370
[ 7654.726298]  [<ffffffffb4f41d79>] ? update_stack_state+0x229/0x370
[ 7654.733195]  [<ffffffffb53fe4b5>] ? kasan_unpoison_shadow+0x35/0x50
[ 7654.740187]  [<ffffffffb53fe62a>] ? kasan_kmalloc+0xaa/0xe0
[ 7654.746406]  [<ffffffffb53fec32>] ? kasan_slab_alloc+0x12/0x20
[ 7654.752914]  [<ffffffffb53fe711>] ? memset+0x31/0x40
[ 7654.758456]  [<ffffffffc165bf92>] ovs_flow_cmd_new+0x2b2/0xf00 [openvswitch]

[snip]

[ 7655.132484] The buggy address belongs to the variable:
[ 7655.138226]  ovs_tunnel_key_lens+0xf0/0xffffffffffffd400 [openvswitch]
[ 7655.145507]
[ 7655.147166] Memory state around the buggy address:
[ 7655.152514]  ffffffffc169eb80: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa
[ 7655.160585]  ffffffffc169ec00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 7655.168644] >ffffffffc169ec80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa fa
[ 7655.176701]                                                              ^
[ 7655.184372]  ffffffffc169ed00: fa fa fa fa 00 00 00 00 fa fa fa fa 00 00 00 05
[ 7655.192431]  ffffffffc169ed80: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
[ 7655.200490] ==================================================================

Reported-by: Hangbin Liu <[email protected]>
Fixes: 982b527 ("openvswitch: Fix mask generation for nested attributes.")
Signed-off-by: Stefano Brivio <[email protected]>
Reviewed-by: Sabrina Dubroca <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Jun 1, 2018
[ Upstream commit 2c0aa08631b86a4678dbc93b9caa5248014b4458 ]

Scenario:
1. Port down and do fail over
2. Ap do rds_bind syscall

PID: 47039  TASK: ffff89887e2fe640  CPU: 47  COMMAND: "kworker/u:6"
 #0 [ffff898e35f159f0] machine_kexec at ffffffff8103abf9
 #1 [ffff898e35f15a60] crash_kexec at ffffffff810b96e3
 #2 [ffff898e35f15b30] oops_end at ffffffff8150f518
 #3 [ffff898e35f15b60] no_context at ffffffff8104854c
 #4 [ffff898e35f15ba0] __bad_area_nosemaphore at ffffffff81048675
 #5 [ffff898e35f15bf0] bad_area_nosemaphore at ffffffff810487d3
 #6 [ffff898e35f15c00] do_page_fault at ffffffff815120b8
 #7 [ffff898e35f15d10] page_fault at ffffffff8150ea95
    [exception RIP: unknown or invalid address]
    RIP: 0000000000000000  RSP: ffff898e35f15dc8  RFLAGS: 00010282
    RAX: 00000000fffffffe  RBX: ffff889b77f6fc00  RCX:ffffffff81c99d88
    RDX: 0000000000000000  RSI: ffff896019ee08e8  RDI:ffff889b77f6fc00
    RBP: ffff898e35f15df0   R8: ffff896019ee08c8  R9:0000000000000000
    R10: 0000000000000400  R11: 0000000000000000  R12:ffff896019ee08c0
    R13: ffff889b77f6fe68  R14: ffffffff81c99d80  R15: ffffffffa022a1e0
    ORIG_RAX: ffffffffffffffff  CS: 0010 SS: 0018
 #8 [ffff898e35f15dc8] cma_ndev_work_handler at ffffffffa022a228 [rdma_cm]
 #9 [ffff898e35f15df8] process_one_work at ffffffff8108a7c6
 #10 [ffff898e35f15e58] worker_thread at ffffffff8108bda0
 #11 [ffff898e35f15ee8] kthread at ffffffff81090fe6

PID: 45659  TASK: ffff880d313d2500  CPU: 31  COMMAND: "oracle_45659_ap"
 #0 [ffff881024ccfc98] __schedule at ffffffff8150bac4
 #1 [ffff881024ccfd40] schedule at ffffffff8150c2cf
 #2 [ffff881024ccfd50] __mutex_lock_slowpath at ffffffff8150cee7
 #3 [ffff881024ccfdc0] mutex_lock at ffffffff8150cdeb
 #4 [ffff881024ccfde0] rdma_destroy_id at ffffffffa022a027 [rdma_cm]
 #5 [ffff881024ccfe10] rds_ib_laddr_check at ffffffffa0357857 [rds_rdma]
 #6 [ffff881024ccfe50] rds_trans_get_preferred at ffffffffa0324c2a [rds]
 #7 [ffff881024ccfe80] rds_bind at ffffffffa031d690 [rds]
 #8 [ffff881024ccfeb0] sys_bind at ffffffff8142a670

PID: 45659                          PID: 47039
rds_ib_laddr_check
  /* create id_priv with a null event_handler */
  rdma_create_id
  rdma_bind_addr
    cma_acquire_dev
      /* add id_priv to cma_dev->id_list */
      cma_attach_to_dev
                                    cma_ndev_work_handler
                                      /* event_hanlder is null */
                                      id_priv->id.event_handler

Signed-off-by: Guanglei Li <[email protected]>
Signed-off-by: Honglei Wang <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
Reviewed-by: Yanjun Zhu <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Jun 1, 2018
[ Upstream commit fca32340a5e8b896f57d41fd94b8b1701df25eb1 ]

Executing command 'perf stat -T -- ls' dumps core on x86 and s390.

Here is the call back chain (done on x86):

 # gdb ./perf
 ....
 (gdb) r stat -T -- ls
...
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff56d1963 in vasprintf () from /lib64/libc.so.6
(gdb) where
 #0  0x00007ffff56d1963 in vasprintf () from /lib64/libc.so.6
 #1  0x00007ffff56ae484 in asprintf () from /lib64/libc.so.6
 #2  0x00000000004f1982 in __parse_events_add_pmu (parse_state=0x7fffffffd580,
    list=0xbfb970, name=0xbf3ef0 "cpu",
    head_config=0xbfb930, auto_merge_stats=false) at util/parse-events.c:1233
 #3  0x00000000004f1c8e in parse_events_add_pmu (parse_state=0x7fffffffd580,
    list=0xbfb970, name=0xbf3ef0 "cpu",
    head_config=0xbfb930) at util/parse-events.c:1288
 #4  0x0000000000537ce3 in parse_events_parse (_parse_state=0x7fffffffd580,
    scanner=0xbf4210) at util/parse-events.y:234
 #5  0x00000000004f2c7a in parse_events__scanner (str=0x6b66c0
    "task-clock,{instructions,cycles,cpu/cycles-t/,cpu/tx-start/}",
    parse_state=0x7fffffffd580, start_token=258) at util/parse-events.c:1673
 #6  0x00000000004f2e23 in parse_events (evlist=0xbe9990, str=0x6b66c0
    "task-clock,{instructions,cycles,cpu/cycles-t/,cpu/tx-start/}", err=0x0)
    at util/parse-events.c:1713
 #7  0x000000000044e137 in add_default_attributes () at builtin-stat.c:2281
 #8  0x000000000044f7b5 in cmd_stat (argc=1, argv=0x7fffffffe3b0) at
    builtin-stat.c:2828
 #9  0x00000000004c8b0f in run_builtin (p=0xab01a0 <commands+288>, argc=4,
    argv=0x7fffffffe3b0) at perf.c:297
 #10 0x00000000004c8d7c in handle_internal_command (argc=4,
    argv=0x7fffffffe3b0) at perf.c:349
 #11 0x00000000004c8ece in run_argv (argcp=0x7fffffffe20c,
   argv=0x7fffffffe200) at perf.c:393
 #12 0x00000000004c929c in main (argc=4, argv=0x7fffffffe3b0) at perf.c:537
(gdb)

It turns out that a NULL pointer is referenced. Here are the
function calls:

  ...
  cmd_stat()
  +---> add_default_attributes()
	+---> parse_events(evsel_list, transaction_attrs, NULL);
	             3rd parameter set to NULL

Function parse_events(xx, xx, struct parse_events_error *err) dives
into a bison generated scanner and creates
parser state information for it first:

   struct parse_events_state parse_state = {
                .list   = LIST_HEAD_INIT(parse_state.list),
                .idx    = evlist->nr_entries,
                .error  = err,   <--- NULL POINTER !!!
                .evlist = evlist,
        };

Now various functions inside the bison scanner are called to end up in
__parse_events_add_pmu(struct parse_events_state *parse_state, ..) with
first parameter being a pointer to above structure definition.

Now the PMU event name is not found (because being executed in a VM) and
this function tries to create an error message with

   asprintf(&parse_state->error.str, ....)

which references a NULL pointer and dumps core.

Fix this by providing a pointer to the necessary error information
instead of NULL. Technically only the else part is needed to avoid the
core dump, just lets be safe...

Signed-off-by: Thomas Richter <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Jun 1, 2018
[ Upstream commit 2bbea6e117357d17842114c65e9a9cf2d13ae8a3 ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Aug 4, 2018
[ Upstream commit 2efd4fca703a6707cad16ab486eaab8fc7f0fd49 ]

Syzbot reported a read beyond the end of the skb head when returning
IPV6_ORIGDSTADDR:

  BUG: KMSAN: kernel-infoleak in put_cmsg+0x5ef/0x860 net/core/scm.c:242
  CPU: 0 PID: 4501 Comm: syz-executor128 Not tainted 4.17.0+ #9
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
  Google 01/01/2011
  Call Trace:
    __dump_stack lib/dump_stack.c:77 [inline]
    dump_stack+0x185/0x1d0 lib/dump_stack.c:113
    kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1125
    kmsan_internal_check_memory+0x138/0x1f0 mm/kmsan/kmsan.c:1219
    kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1261
    copy_to_user include/linux/uaccess.h:184 [inline]
    put_cmsg+0x5ef/0x860 net/core/scm.c:242
    ip6_datagram_recv_specific_ctl+0x1cf3/0x1eb0 net/ipv6/datagram.c:719
    ip6_datagram_recv_ctl+0x41c/0x450 net/ipv6/datagram.c:733
    rawv6_recvmsg+0x10fb/0x1460 net/ipv6/raw.c:521
    [..]

This logic and its ipv4 counterpart read the destination port from
the packet at skb_transport_offset(skb) + 4.

With MSG_MORE and a local SOCK_RAW sender, syzbot was able to cook a
packet that stores headers exactly up to skb_transport_offset(skb) in
the head and the remainder in a frag.

Call pskb_may_pull before accessing the pointer to ensure that it lies
in skb head.

Link: http://lkml.kernel.org/r/CAF=yD-LEJwZj5a1-bAAj2Oy_hKmGygV6rsJ_WOrAYnv-fnayiQ@mail.gmail.com
Reported-by: [email protected]
Signed-off-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Aug 31, 2018
commit 89da619bc18d79bca5304724c11d4ba3b67ce2c6 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: [email protected]
Signed-off-by: Jiang Biao <[email protected]>
Signed-off-by: Huang Chong <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Aug 31, 2018
commit ace0c791e6c3cf5ef37cad2df69f0d90ccc40ffb upstream.

Konstantin Khlebnikov <[email protected]> writes:
> This patch has locking problem. I've got lockdep splat under LTP.
>
> [ 6633.115456] ======================================================
> [ 6633.115502] [ INFO: possible circular locking dependency detected ]
> [ 6633.115553] 4.9.10-debug+ #9 Tainted: G             L
> [ 6633.115584] -------------------------------------------------------
> [ 6633.115627] ksm02/284980 is trying to acquire lock:
> [ 6633.115659]  (&sb->s_type->i_lock_key#4){+.+...}, at: [<ffffffff816bc1ce>] igrab+0x1e/0x80
> [ 6633.115834] but task is already holding lock:
> [ 6633.115882]  (sysctl_lock){+.+...}, at: [<ffffffff817e379b>] unregister_sysctl_table+0x6b/0x110
> [ 6633.116026] which lock already depends on the new lock.
> [ 6633.116026]
> [ 6633.116080]
> [ 6633.116080] the existing dependency chain (in reverse order) is:
> [ 6633.116117]
> -> #2 (sysctl_lock){+.+...}:
> -> #1 (&(&dentry->d_lockref.lock)->rlock){+.+...}:
> -> #0 (&sb->s_type->i_lock_key#4){+.+...}:
>
> d_lock nests inside i_lock
> sysctl_lock nests inside d_lock in d_compare
>
> This patch adds i_lock nesting inside sysctl_lock.

Al Viro <[email protected]> replied:
> Once ->unregistering is set, you can drop sysctl_lock just fine.  So I'd
> try something like this - use rcu_read_lock() in proc_sys_prune_dcache(),
> drop sysctl_lock() before it and regain after.  Make sure that no inodes
> are added to the list ones ->unregistering has been set and use RCU list
> primitives for modifying the inode list, with sysctl_lock still used to
> serialize its modifications.
>
> Freeing struct inode is RCU-delayed (see proc_destroy_inode()), so doing
> igrab() is safe there.  Since we don't drop inode reference until after we'd
> passed beyond it in the list, list_for_each_entry_rcu() should be fine.

I agree with Al Viro's analsysis of the situtation.

Fixes: d6cffbbe9a7e ("proc/sysctl: prune stale dentries during unregistering")
Reported-by: Konstantin Khlebnikov <[email protected]>
Tested-by: Konstantin Khlebnikov <[email protected]>
Suggested-by: Al Viro <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Sep 11, 2018
[ Upstream commit 934140ab028713a61de8bca58c05332416d037d1 ]

cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview.  However, it has no ref on that monitor object or on the
associated operation.

What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object.  However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.

If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.

Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock.  The op can then be enqueued after the lock is
dropped.

The bug can manifest in one of a couple of ways.  The first manifestation
looks like:

 FS-Cache:
 FS-Cache: Assertion failed
 FS-Cache: 6 == 5 is false
 ------------[ cut here ]------------
 kernel BUG at fs/fscache/operation.c:494!
 RIP: 0010:fscache_put_operation+0x1e3/0x1f0
 ...
 fscache_op_work_func+0x26/0x50
 process_one_work+0x131/0x290
 worker_thread+0x45/0x360
 kthread+0xf8/0x130
 ? create_worker+0x190/0x190
 ? kthread_cancel_work_sync+0x10/0x10
 ret_from_fork+0x1f/0x30

This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().

The bug can also manifest like the following:

 kernel BUG at fs/fscache/operation.c:69!
 ...
    [exception RIP: fscache_enqueue_operation+246]
 ...
 #7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
 #8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
 #9 [ffff883fff083c48] __wake_up_common at ffffffff810af028

I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.

Fixes: 9ae326a ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Lei Xue <[email protected]>
Reported-by: Vegard Nossum <[email protected]>
Reported-by: Anthony DeRobertis <[email protected]>
Reported-by: NeilBrown <[email protected]>
Reported-by: Daniel Axtens <[email protected]>
Reported-by: Kiran Kumar Modukuri <[email protected]>
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Daniel Axtens <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Sep 18, 2018
commit a5ba1d95e46ecaea638ddd7cd144107c783acb5d upstream.

We have reports of the following crash:

    PID: 7 TASK: ffff88085c6d61c0 CPU: 1 COMMAND: "kworker/u25:0"
    #0 [ffff88085c6db710] machine_kexec at ffffffff81046239
    #1 [ffff88085c6db760] crash_kexec at ffffffff810fc248
    #2 [ffff88085c6db830] oops_end at ffffffff81008ae7
    #3 [ffff88085c6db860] no_context at ffffffff81050b8f
    #4 [ffff88085c6db8b0] __bad_area_nosemaphore at ffffffff81050d75
    #5 [ffff88085c6db900] bad_area_nosemaphore at ffffffff81050e83
    #6 [ffff88085c6db910] __do_page_fault at ffffffff8105132e
    #7 [ffff88085c6db9b0] do_page_fault at ffffffff8105152c
    #8 [ffff88085c6db9c0] page_fault at ffffffff81a3f122
    [exception RIP: uart_put_char+149]
    RIP: ffffffff814b67b5 RSP: ffff88085c6dba78 RFLAGS: 00010006
    RAX: 0000000000000292 RBX: ffffffff827c5120 RCX: 0000000000000081
    RDX: 0000000000000000 RSI: 000000000000005f RDI: ffffffff827c5120
    RBP: ffff88085c6dba98 R8: 000000000000012c R9: ffffffff822ea320
    R10: ffff88085fe4db04 R11: 0000000000000001 R12: ffff881059f9c000
    R13: 0000000000000001 R14: 000000000000005f R15: 0000000000000fba
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
    #9 [ffff88085c6dbaa0] tty_put_char at ffffffff81497544
    #10 [ffff88085c6dbac0] do_output_char at ffffffff8149c91c
    #11 [ffff88085c6dbae0] __process_echoes at ffffffff8149cb8b
    #12 [ffff88085c6dbb30] commit_echoes at ffffffff8149cdc2
    #13 [ffff88085c6dbb60] n_tty_receive_buf_fast at ffffffff8149e49b
    #14 [ffff88085c6dbbc0] __receive_buf at ffffffff8149ef5a
    #15 [ffff88085c6dbc20] n_tty_receive_buf_common at ffffffff8149f016
    #16 [ffff88085c6dbca0] n_tty_receive_buf2 at ffffffff8149f194
    #17 [ffff88085c6dbcb0] flush_to_ldisc at ffffffff814a238a
    #18 [ffff88085c6dbd50] process_one_work at ffffffff81090be2
    #19 [ffff88085c6dbe20] worker_thread at ffffffff81091b4d
    #20 [ffff88085c6dbeb0] kthread at ffffffff81096384
    #21 [ffff88085c6dbf50] ret_from_fork at ffffffff81a3d69f​

after slogging through some dissasembly:

ffffffff814b6720 <uart_put_char>:
ffffffff814b6720:	55                   	push   %rbp
ffffffff814b6721:	48 89 e5             	mov    %rsp,%rbp
ffffffff814b6724:	48 83 ec 20          	sub    $0x20,%rsp
ffffffff814b6728:	48 89 1c 24          	mov    %rbx,(%rsp)
ffffffff814b672c:	4c 89 64 24 08       	mov    %r12,0x8(%rsp)
ffffffff814b6731:	4c 89 6c 24 10       	mov    %r13,0x10(%rsp)
ffffffff814b6736:	4c 89 74 24 18       	mov    %r14,0x18(%rsp)
ffffffff814b673b:	e8 b0 8e 58 00       	callq  ffffffff81a3f5f0 <mcount>
ffffffff814b6740:	4c 8b a7 88 02 00 00 	mov    0x288(%rdi),%r12
ffffffff814b6747:	45 31 ed             	xor    %r13d,%r13d
ffffffff814b674a:	41 89 f6             	mov    %esi,%r14d
ffffffff814b674d:	49 83 bc 24 70 01 00 	cmpq   $0x0,0x170(%r12)
ffffffff814b6754:	00 00
ffffffff814b6756:	49 8b 9c 24 80 01 00 	mov    0x180(%r12),%rbx
ffffffff814b675d:	00
ffffffff814b675e:	74 2f                	je     ffffffff814b678f <uart_put_char+0x6f>
ffffffff814b6760:	48 89 df             	mov    %rbx,%rdi
ffffffff814b6763:	e8 a8 67 58 00       	callq  ffffffff81a3cf10 <_raw_spin_lock_irqsave>
ffffffff814b6768:	41 8b 8c 24 78 01 00 	mov    0x178(%r12),%ecx
ffffffff814b676f:	00
ffffffff814b6770:	89 ca                	mov    %ecx,%edx
ffffffff814b6772:	f7 d2                	not    %edx
ffffffff814b6774:	41 03 94 24 7c 01 00 	add    0x17c(%r12),%edx
ffffffff814b677b:	00
ffffffff814b677c:	81 e2 ff 0f 00 00    	and    $0xfff,%edx
ffffffff814b6782:	75 23                	jne    ffffffff814b67a7 <uart_put_char+0x87>
ffffffff814b6784:	48 89 c6             	mov    %rax,%rsi
ffffffff814b6787:	48 89 df             	mov    %rbx,%rdi
ffffffff814b678a:	e8 e1 64 58 00       	callq  ffffffff81a3cc70 <_raw_spin_unlock_irqrestore>
ffffffff814b678f:	44 89 e8             	mov    %r13d,%eax
ffffffff814b6792:	48 8b 1c 24          	mov    (%rsp),%rbx
ffffffff814b6796:	4c 8b 64 24 08       	mov    0x8(%rsp),%r12
ffffffff814b679b:	4c 8b 6c 24 10       	mov    0x10(%rsp),%r13
ffffffff814b67a0:	4c 8b 74 24 18       	mov    0x18(%rsp),%r14
ffffffff814b67a5:	c9                   	leaveq
ffffffff814b67a6:	c3                   	retq
ffffffff814b67a7:	49 8b 94 24 70 01 00 	mov    0x170(%r12),%rdx
ffffffff814b67ae:	00
ffffffff814b67af:	48 63 c9             	movslq %ecx,%rcx
ffffffff814b67b2:	41 b5 01             	mov    $0x1,%r13b
ffffffff814b67b5:	44 88 34 0a          	mov    %r14b,(%rdx,%rcx,1)
ffffffff814b67b9:	41 8b 94 24 78 01 00 	mov    0x178(%r12),%edx
ffffffff814b67c0:	00
ffffffff814b67c1:	83 c2 01             	add    $0x1,%edx
ffffffff814b67c4:	81 e2 ff 0f 00 00    	and    $0xfff,%edx
ffffffff814b67ca:	41 89 94 24 78 01 00 	mov    %edx,0x178(%r12)
ffffffff814b67d1:	00
ffffffff814b67d2:	eb b0                	jmp    ffffffff814b6784 <uart_put_char+0x64>
ffffffff814b67d4:	66 66 66 2e 0f 1f 84 	data32 data32 nopw %cs:0x0(%rax,%rax,1)
ffffffff814b67db:	00 00 00 00 00

for our build, this is crashing at:

    circ->buf[circ->head] = c;

Looking in uart_port_startup(), it seems that circ->buf (state->xmit.buf)
protected by the "per-port mutex", which based on uart_port_check() is
state->port.mutex. Indeed, the lock acquired in uart_put_char() is
uport->lock, i.e. not the same lock.

Anyway, since the lock is not acquired, if uart_shutdown() is called, the
last chunk of that function may release state->xmit.buf before its assigned
to null, and cause the race above.

To fix it, let's lock uport->lock when allocating/deallocating
state->xmit.buf in addition to the per-port mutex.

v2: switch to locking uport->lock on allocation/deallocation instead of
    locking the per-port mutex in uart_put_char. Note that since
    uport->lock is a spin lock, we have to switch the allocation to
    GFP_ATOMIC.
v3: move the allocation outside the lock, so we can switch back to
    GFP_KERNEL

Signed-off-by: Tycho Andersen <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Nov 14, 2018
[ Upstream commit 1f80bd6a6cc8358b81194e1f5fc16449947396ec ]

The locking order of vlan_rwsem (LOCK A) and then rtnl (LOCK B),
contradicts other flows such as ipoib_open possibly causing a deadlock.
To prevent this deadlock heavy flush is called with RTNL locked and
only then tries to acquire vlan_rwsem.
This deadlock is possible only when there are child interfaces.

[  140.941758] ======================================================
[  140.946276] WARNING: possible circular locking dependency detected
[  140.950950] 4.15.0-rc1+ #9 Tainted: G           O
[  140.954797] ------------------------------------------------------
[  140.959424] kworker/u32:1/146 is trying to acquire lock:
[  140.963450]  (rtnl_mutex){+.+.}, at: [<ffffffffc083516a>] __ipoib_ib_dev_flush+0x2da/0x4e0 [ib_ipoib]
[  140.970006]
but task is already holding lock:
[  140.975141]  (&priv->vlan_rwsem){++++}, at: [<ffffffffc0834ee1>] __ipoib_ib_dev_flush+0x51/0x4e0 [ib_ipoib]
[  140.982105]
which lock already depends on the new lock.
[  140.990023]
the existing dependency chain (in reverse order) is:
[  140.998650]
-> #1 (&priv->vlan_rwsem){++++}:
[  141.005276]        down_read+0x4d/0xb0
[  141.009560]        ipoib_open+0xad/0x120 [ib_ipoib]
[  141.014400]        __dev_open+0xcb/0x140
[  141.017919]        __dev_change_flags+0x1a4/0x1e0
[  141.022133]        dev_change_flags+0x23/0x60
[  141.025695]        devinet_ioctl+0x704/0x7d0
[  141.029156]        sock_do_ioctl+0x20/0x50
[  141.032526]        sock_ioctl+0x221/0x300
[  141.036079]        do_vfs_ioctl+0xa6/0x6d0
[  141.039656]        SyS_ioctl+0x74/0x80
[  141.042811]        entry_SYSCALL_64_fastpath+0x1f/0x96
[  141.046891]
-> #0 (rtnl_mutex){+.+.}:
[  141.051701]        lock_acquire+0xd4/0x220
[  141.055212]        __mutex_lock+0x88/0x970
[  141.058631]        __ipoib_ib_dev_flush+0x2da/0x4e0 [ib_ipoib]
[  141.063160]        __ipoib_ib_dev_flush+0x71/0x4e0 [ib_ipoib]
[  141.067648]        process_one_work+0x1f5/0x610
[  141.071429]        worker_thread+0x4a/0x3f0
[  141.074890]        kthread+0x141/0x180
[  141.078085]        ret_from_fork+0x24/0x30
[  141.081559]

other info that might help us debug this:
[  141.088967]  Possible unsafe locking scenario:
[  141.094280]        CPU0                    CPU1
[  141.097953]        ----                    ----
[  141.101640]   lock(&priv->vlan_rwsem);
[  141.104771]                                lock(rtnl_mutex);
[  141.109207]                                lock(&priv->vlan_rwsem);
[  141.114032]   lock(rtnl_mutex);
[  141.116800]
 *** DEADLOCK ***

Fixes: b4b678b06f6e ("IB/ipoib: Grab rtnl lock on heavy flush when calling ndo_open/stop")
Signed-off-by: Alex Vesker <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
sys-oak pushed a commit that referenced this issue Nov 20, 2018
commit 374b0e2d6ba5da7fd1cadb3247731ff27d011f6f upstream.

When we hit an I/O error in free_log_tree->walk_log_tree during file system
shutdown we can crash due to there not being a valid transaction handle.

Use btrfs_handle_fs_error when there's no transaction handle to use.

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000060
  IP: free_log_tree+0xd2/0x140 [btrfs]
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
  Modules linked in: <modules>
  CPU: 2 PID: 23544 Comm: umount Tainted: G        W        4.12.14-kvmsmall #9 SLE15 (unreleased)
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
  task: ffff96bfd3478880 task.stack: ffffa7cf40d78000
  RIP: 0010:free_log_tree+0xd2/0x140 [btrfs]
  RSP: 0018:ffffa7cf40d7bd10 EFLAGS: 00010282
  RAX: 00000000fffffffb RBX: 00000000fffffffb RCX: 0000000000000002
  RDX: 0000000000000000 RSI: ffff96c02f07d4c8 RDI: 0000000000000282
  RBP: ffff96c013cf1000 R08: ffff96c02f07d4c8 R09: ffff96c02f07d4d0
  R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
  R13: ffff96c005e800c0 R14: ffffa7cf40d7bdb8 R15: 0000000000000000
  FS:  00007f17856bcfc0(0000) GS:ffff96c03f600000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000060 CR3: 0000000045ed6002 CR4: 00000000003606e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   ? wait_for_writer+0xb0/0xb0 [btrfs]
   btrfs_free_log+0x17/0x30 [btrfs]
   btrfs_drop_and_free_fs_root+0x9a/0xe0 [btrfs]
   btrfs_free_fs_roots+0xc0/0x130 [btrfs]
   ? wait_for_completion+0xf2/0x100
   close_ctree+0xea/0x2e0 [btrfs]
   ? kthread_stop+0x161/0x260
   generic_shutdown_super+0x6c/0x120
   kill_anon_super+0xe/0x20
   btrfs_kill_super+0x13/0x100 [btrfs]
   deactivate_locked_super+0x3f/0x70
   cleanup_mnt+0x3b/0x70
   task_work_run+0x78/0x90
   exit_to_usermode_loop+0x77/0xa6
   do_syscall_64+0x1c5/0x1e0
   entry_SYSCALL_64_after_hwframe+0x42/0xb7
  RIP: 0033:0x7f1784f90827
  RSP: 002b:00007ffdeeb03118 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  RAX: 0000000000000000 RBX: 0000556a60c62970 RCX: 00007f1784f90827
  RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000556a60c62b50
  RBP: 0000000000000000 R08: 0000000000000005 R09: 00000000ffffffff
  R10: 0000556a60c63900 R11: 0000000000000246 R12: 0000556a60c62b50
  R13: 00007f17854a81c4 R14: 0000000000000000 R15: 0000000000000000
  RIP: free_log_tree+0xd2/0x140 [btrfs] RSP: ffffa7cf40d7bd10
  CR2: 0000000000000060

Fixes: 681ae50 ("Btrfs: cleanup reserved space when freeing tree log on error")
CC: <[email protected]> # v3.13
Signed-off-by: Jeff Mahoney <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
sys-oak pushed a commit that referenced this issue Dec 21, 2018
[ Upstream commit c5a94f434c82529afda290df3235e4d85873c5b4 ]

It was observed that a process blocked indefintely in
__fscache_read_or_alloc_page(), waiting for FSCACHE_COOKIE_LOOKING_UP
to be cleared via fscache_wait_for_deferred_lookup().

At this time, ->backing_objects was empty, which would normaly prevent
__fscache_read_or_alloc_page() from getting to the point of waiting.
This implies that ->backing_objects was cleared *after*
__fscache_read_or_alloc_page was was entered.

When an object is "killed" and then "dropped",
FSCACHE_COOKIE_LOOKING_UP is cleared in fscache_lookup_failure(), then
KILL_OBJECT and DROP_OBJECT are "called" and only in DROP_OBJECT is
->backing_objects cleared.  This leaves a window where
something else can set FSCACHE_COOKIE_LOOKING_UP and
__fscache_read_or_alloc_page() can start waiting, before
->backing_objects is cleared

There is some uncertainty in this analysis, but it seems to be fit the
observations.  Adding the wake in this patch will be handled correctly
by __fscache_read_or_alloc_page(), as it checks if ->backing_objects
is empty again, after waiting.

Customer which reported the hang, also report that the hang cannot be
reproduced with this fix.

The backtrace for the blocked process looked like:

PID: 29360  TASK: ffff881ff2ac0f80  CPU: 3   COMMAND: "zsh"
 #0 [ffff881ff43efbf8] schedule at ffffffff815e56f1
 #1 [ffff881ff43efc58] bit_wait at ffffffff815e64ed
 #2 [ffff881ff43efc68] __wait_on_bit at ffffffff815e61b8
 #3 [ffff881ff43efca0] out_of_line_wait_on_bit at ffffffff815e625e
 #4 [ffff881ff43efd08] fscache_wait_for_deferred_lookup at ffffffffa04f2e8f [fscache]
 #5 [ffff881ff43efd18] __fscache_read_or_alloc_page at ffffffffa04f2ffe [fscache]
 #6 [ffff881ff43efd58] __nfs_readpage_from_fscache at ffffffffa0679668 [nfs]
 #7 [ffff881ff43efd78] nfs_readpage at ffffffffa067092b [nfs]
 #8 [ffff881ff43efda0] generic_file_read_iter at ffffffff81187a73
 #9 [ffff881ff43efe50] nfs_file_read at ffffffffa066544b [nfs]
#10 [ffff881ff43efe70] __vfs_read at ffffffff811fc756
#11 [ffff881ff43efee8] vfs_read at ffffffff811fccfa
#12 [ffff881ff43eff18] sys_read at ffffffff811fda62
#13 [ffff881ff43eff50] entry_SYSCALL_64_fastpath at ffffffff815e986e

Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: David Howells <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
sys-oak pushed a commit that referenced this issue Feb 1, 2019
|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 1, irqs_disabled(): 0, pid: 3194, name: rpc.nfsd
|Preemption disabled at:[<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
|CPU: 6 PID: 3194 Comm: rpc.nfsd Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409630000 ffff8800d9a33c78 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff8800d9a33c98 ffffffff81073c86 ffff880408dd6008
| ffff880408dd6000 ffff8800d9a33cb8 ffffffff815c3d84 ffff88040b3ac000
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d84>] rt_spin_lock+0x24/0x50
| [<ffffffffa06beec0>] svc_xprt_do_enqueue+0x80/0x230 [sunrpc]
| [<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
| [<ffffffffa06c03ed>] svc_add_new_perm_xprt+0x6d/0x80 [sunrpc]
| [<ffffffffa06b2693>] svc_addsock+0x143/0x200 [sunrpc]
| [<ffffffffa072e69c>] write_ports+0x28c/0x340 [nfsd]
| [<ffffffffa072d2ac>] nfsctl_transaction_write+0x4c/0x80 [nfsd]
| [<ffffffff8117ee83>] vfs_write+0xb3/0x1d0
| [<ffffffff8117f889>] SyS_write+0x49/0xb0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b


Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
sys-oak pushed a commit that referenced this issue Feb 1, 2019
Locking functions previously using read_lock_irq()/read_lock_irqsave() were
changed to local_irq_disable/save(), leading to gripes.  Use nort variants.

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 0, irqs_disabled(): 1, pid: 5947, name: alsa-sink-ALC88
|CPU: 5 PID: 5947 Comm: alsa-sink-ALC88 Not tainted 3.18.7-rt1 #9
|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
| ffff880409316240 ffff88040866fa38 ffffffff815bdeb5 0000000000000002
| 0000000000000000 ffff88040866fa58 ffffffff81073c86 ffffffffa03b2640
| ffff88040239ec00 ffff88040866fa78 ffffffff815c3d34 ffffffffa03b2640
|Call Trace:
| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
| [<ffffffff815c3d34>] __rt_spin_lock+0x24/0x50
| [<ffffffff815c4044>] rt_read_lock+0x34/0x40
| [<ffffffffa03a2979>] snd_pcm_stream_lock+0x29/0x70 [snd_pcm]
| [<ffffffffa03a355d>] snd_pcm_playback_poll+0x5d/0x120 [snd_pcm]
| [<ffffffff811937a2>] do_sys_poll+0x322/0x5b0
| [<ffffffff81193d48>] SyS_ppoll+0x1a8/0x1c0
| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
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