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zfs destroy of dataset with mountpoint fails with busy dataset #9

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Rudd-O opened this issue Jan 17, 2013 · 3 comments
Open

zfs destroy of dataset with mountpoint fails with busy dataset #9

Rudd-O opened this issue Jan 17, 2013 · 3 comments

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@Rudd-O
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Rudd-O commented Jan 17, 2013

might be related to systemd integration (destroy unmounts then attempts to destroy but systemd might mount the fs again or has an invisible automount point there, even though the fs does not appear mounted)

rule out hypothesis by creating dataset, rebooting, attempting to destroy, and if it fails, attempt to tellll systemd to let go of his idea of the dataset, and try again.

destroy works if the dataset is set to legacy or none and the system is rebooted and then the dataset is destroyed (did not test setting to legacy and then deleting right away)
@Rudd-O
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Rudd-O commented Jan 28, 2013

I think I know what the problem with ZFS destroy is:
systemd generator appeas to be creating automount units which activate when destroying a dataset.

the fix should be to eliminate the automount units as they are not strictly necessary.

@Rudd-O
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Rudd-O commented Jan 28, 2013

test potential fix. it is also the case that systemd's mount unit file needs to be deleted, and systemde needs to be reloaded, when a dataset is destroyed

@Rudd-O
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Rudd-O commented Jan 29, 2013

automount units are not involved. also for some reason i can only repro on my NAS but not on my desktop machine.

Rudd-O pushed a commit that referenced this issue Jan 18, 2020
@ahrens @behlendorf
Fix use-after-free of vd_path in spa_vdev_remove()
9bb0d89 
After spa_vdev_remove_aux() is called, the config nvlist is no longer
valid, as it's been replaced by the new one (with the specified device
removed).  Therefore any pointers into the nvlist are no longer valid.
So we can't save the result of
`fnvlist_lookup_string(nv, ZPOOL_CONFIG_PATH)` (in vd_path) across the
call to spa_vdev_remove_aux().

Instead, use spa_strdup() to save a copy of the string before calling
spa_vdev_remove_aux.

Found by AddressSanitizer:

ERROR: AddressSanitizer: heap-use-after-free on address ...
READ of size 34 at 0x608000a1fcd0 thread T686
    #0 0x7fe88b0c166d  (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x5166d)
    #1 0x7fe88a5acd6e in spa_strdup spa_misc.c:1447
    #2 0x7fe88a688034 in spa_vdev_remove vdev_removal.c:2259
    #3 0x55ffbc7748f8 in ztest_vdev_aux_add_remove ztest.c:3229
    #4 0x55ffbc769fba in ztest_execute ztest.c:6714
    #5 0x55ffbc779a90 in ztest_thread ztest.c:6761
    #6 0x7fe889cbc6da in start_thread
    #7 0x7fe8899e588e in __clone

0x608000a1fcd0 is located 48 bytes inside of 88-byte region
freed by thread T686 here:
    #0 0x7fe88b14e7b8 in __interceptor_free
    #1 0x7fe88ae541c5 in nvlist_free nvpair.c:874
    #2 0x7fe88ae543ba in nvpair_free nvpair.c:844
    #3 0x7fe88ae57400 in nvlist_remove_nvpair nvpair.c:978
    #4 0x7fe88a683c81 in spa_vdev_remove_aux vdev_removal.c:185
    #5 0x7fe88a68857c in spa_vdev_remove vdev_removal.c:2221
    #6 0x55ffbc7748f8 in ztest_vdev_aux_add_remove ztest.c:3229
    #7 0x55ffbc769fba in ztest_execute ztest.c:6714
    #8 0x55ffbc779a90 in ztest_thread ztest.c:6761
    #9 0x7fe889cbc6da in start_thread

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Matthew Ahrens <[email protected]>
Closes openzfs#9706
Rudd-O pushed a commit that referenced this issue Nov 19, 2023
@rob-wing
FreeBSD: don't verify recycled vnode for zfs control directory
28251d8 
Under certain loads, the following panic is hit:

    panic: page fault
    KDB: stack backtrace:
    #0 0xffffffff805db025 at kdb_backtrace+0x65
    #1 0xffffffff8058e86f at vpanic+0x17f
    #2 0xffffffff8058e6e3 at panic+0x43
    #3 0xffffffff808adc15 at trap_fatal+0x385
    #4 0xffffffff808adc6f at trap_pfault+0x4f
    #5 0xffffffff80886da8 at calltrap+0x8
    #6 0xffffffff80669186 at vgonel+0x186
    #7 0xffffffff80669841 at vgone+0x31
    #8 0xffffffff8065806d at vfs_hash_insert+0x26d
    #9 0xffffffff81a39069 at sfs_vgetx+0x149
    #10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #11 0xffffffff8065a28c at lookup+0x45c
    #12 0xffffffff806594b9 at namei+0x259
    #13 0xffffffff80676a33 at kern_statat+0xf3
    #14 0xffffffff8067712f at sys_fstatat+0x2f
    openzfs#15 0xffffffff808ae50c at amd64_syscall+0x10c
    openzfs#16 0xffffffff808876bb at fast_syscall_common+0xf8

The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.

After adding the necessary vop, the bug progresses to the following
panic:

    panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
    cpuid = 17
    KDB: stack backtrace:
    #0 0xffffffff805e29c5 at kdb_backtrace+0x65
    #1 0xffffffff8059620f at vpanic+0x17f
    #2 0xffffffff81a27f4a at spl_panic+0x3a
    #3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    #4 0xffffffff8066fdee at vinactivef+0xde
    #5 0xffffffff80670b8a at vgonel+0x1ea
    #6 0xffffffff806711e1 at vgone+0x31
    #7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    #8 0xffffffff81a39069 at sfs_vgetx+0x149
    #9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #10 0xffffffff80661c2c at lookup+0x45c
    #11 0xffffffff80660e59 at namei+0x259
    #12 0xffffffff8067e3d3 at kern_statat+0xf3
    #13 0xffffffff8067eacf at sys_fstatat+0x2f
    #14 0xffffffff808b5ecc at amd64_syscall+0x10c
    openzfs#15 0xffffffff8088f07b at fast_syscall_common+0xf8

This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.

Fix this by dropping the assertion.

FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <[email protected]>
Reviewed-by: Mateusz Guzik <[email protected]>
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Rob Wing <[email protected]>
Co-authored-by: Rob Wing <[email protected]>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
Rudd-O pushed a commit that referenced this issue Feb 5, 2024
@rob-wing @behlendorf
FreeBSD: don't verify recycled vnode for zfs control directory
f786232 
Under certain loads, the following panic is hit:

    panic: page fault
    KDB: stack backtrace:
    #0 0xffffffff805db025 at kdb_backtrace+0x65
    #1 0xffffffff8058e86f at vpanic+0x17f
    #2 0xffffffff8058e6e3 at panic+0x43
    #3 0xffffffff808adc15 at trap_fatal+0x385
    #4 0xffffffff808adc6f at trap_pfault+0x4f
    #5 0xffffffff80886da8 at calltrap+0x8
    #6 0xffffffff80669186 at vgonel+0x186
    #7 0xffffffff80669841 at vgone+0x31
    #8 0xffffffff8065806d at vfs_hash_insert+0x26d
    #9 0xffffffff81a39069 at sfs_vgetx+0x149
    #10 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #11 0xffffffff8065a28c at lookup+0x45c
    #12 0xffffffff806594b9 at namei+0x259
    #13 0xffffffff80676a33 at kern_statat+0xf3
    #14 0xffffffff8067712f at sys_fstatat+0x2f
    openzfs#15 0xffffffff808ae50c at amd64_syscall+0x10c
    openzfs#16 0xffffffff808876bb at fast_syscall_common+0xf8

The page fault occurs because vgonel() will call VOP_CLOSE() for active
vnodes. For this reason, define vop_close for zfsctl_ops_snapshot. While
here, define vop_open for consistency.

After adding the necessary vop, the bug progresses to the following
panic:

    panic: VERIFY3(vrecycle(vp) == 1) failed (0 == 1)
    cpuid = 17
    KDB: stack backtrace:
    #0 0xffffffff805e29c5 at kdb_backtrace+0x65
    #1 0xffffffff8059620f at vpanic+0x17f
    #2 0xffffffff81a27f4a at spl_panic+0x3a
    #3 0xffffffff81a3a4d0 at zfsctl_snapshot_inactive+0x40
    #4 0xffffffff8066fdee at vinactivef+0xde
    #5 0xffffffff80670b8a at vgonel+0x1ea
    #6 0xffffffff806711e1 at vgone+0x31
    #7 0xffffffff8065fa0d at vfs_hash_insert+0x26d
    #8 0xffffffff81a39069 at sfs_vgetx+0x149
    #9 0xffffffff81a39c54 at zfsctl_snapdir_lookup+0x1e4
    #10 0xffffffff80661c2c at lookup+0x45c
    #11 0xffffffff80660e59 at namei+0x259
    #12 0xffffffff8067e3d3 at kern_statat+0xf3
    #13 0xffffffff8067eacf at sys_fstatat+0x2f
    #14 0xffffffff808b5ecc at amd64_syscall+0x10c
    openzfs#15 0xffffffff8088f07b at fast_syscall_common+0xf8

This is caused by a race condition that can occur when allocating a new
vnode and adding that vnode to the vfs hash. If the newly created vnode
loses the race when being inserted into the vfs hash, it will not be
recycled as its usecount is greater than zero, hitting the above
assertion.

Fix this by dropping the assertion.

FreeBSD-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252700
Reviewed-by: Andriy Gapon <[email protected]>
Reviewed-by: Mateusz Guzik <[email protected]>
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Rob Wing <[email protected]>
Co-authored-by: Rob Wing <[email protected]>
Submitted-by: Klara, Inc.
Sponsored-by: rsync.net
Closes openzfs#14501
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