travis: test x86 LTS #35

commit 81b45683487a ("compiler.h: give up __compiletime_assert_fallback()")

is needed because travis kills the job otherwise due to log spew. See
build 271.

> The job exceeded the maximum log length, and has been terminated.

The proper fix is to send the backport, TODO.

.travis.yml

@@ -35,15 +35,25 @@ matrix:
     #- name: "ARCH=arm64 REPO=4.19"
       #env: ARCH=arm64 REPO=4.19
       #if: type = cron
+    - name: "ARCH=x86_64 REPO=4.19"
+      env: ARCH=x86_64 REPO=4.19
+      if: type = cron
     - name: "ARCH=arm64 REPO=4.14"
       env: ARCH=arm64 REPO=4.14
       if: type = cron
+    #- name: "ARCH=x86_64 REPO=4.14"
+      #env: ARCH=x86_64 REPO=4.14
+      #if: type = cron
     #- name: "ARCH=arm64 REPO=4.9"
       #env: ARCH=arm64 REPO=4.9
       #if: type = cron
+    #- name: "ARCH=x86_64 REPO=4.9"
+      #env: ARCH=x86_64 REPO=4.9
     #- name: "ARCH=arm64 REPO=4.4"
       #env: ARCH=arm64 REPO=4.4
       #if: type = cron
+    #- name: "ARCH=x86_64 REPO=4.4"
+      #env: ARCH=x86_64 REPO=4.4
 compiler: gcc
 os: linux
 dist: trusty

patches/4.19/x86_64/0001-DO-NOT-UPSTREAM-x86-Avoid-warnings-errors-due-to-lac.patch

@@ -0,0 +1 @@
+../../linux/x86_64/0001-DO-NOT-UPSTREAM-x86-Avoid-warnings-errors-due-to-lac.patch

patches/4.19/x86_64/0002-compiler.h-give-up-__compiletime_assert_fallback.patch

@@ -0,0 +1,83 @@
+From 81b45683487a51b0f4d3b29d37f20d6d078544e4 Mon Sep 17 00:00:00 2001
+From: Masahiro Yamada <[email protected]>
+Date: Sun, 26 Aug 2018 03:16:29 +0900
+Subject: [PATCH] compiler.h: give up __compiletime_assert_fallback()
+
+__compiletime_assert_fallback() is supposed to stop building earlier
+by using the negative-array-size method in case the compiler does not
+support "error" attribute, but has never worked like that.
+
+You can simply try:
+
+    BUILD_BUG_ON(1);
+
+GCC immediately terminates the build, but Clang does not report
+anything because Clang does not support the "error" attribute now.
+It will later fail at link time, but __compiletime_assert_fallback()
+is not working at least.
+
+The root cause is commit 1d6a0d19c855 ("bug.h: prevent double evaluation
+of `condition' in BUILD_BUG_ON").  Prior to that commit, BUILD_BUG_ON()
+was checked by the negative-array-size method *and* the link-time trick.
+Since that commit, the negative-array-size is not effective because
+'__cond' is no longer constant.  As the comment in <linux/build_bug.h>
+says, GCC (and Clang as well) only emits the error for obvious cases.
+
+When '__cond' is a variable,
+
+    ((void)sizeof(char[1 - 2 * __cond]))
+
+... is not obvious for the compiler to know the array size is negative.
+
+Reverting that commit would break BUILD_BUG() because negative-size-array
+is evaluated before the code is optimized out.
+
+Let's give up __compiletime_assert_fallback().  This commit does not
+change the current behavior since it just rips off the useless code.
+
+Signed-off-by: Masahiro Yamada <[email protected]>
+Reviewed-by: Kees Cook <[email protected]>
+Reviewed-by: Nick Desaulniers <[email protected]>
+Signed-off-by: Kees Cook <[email protected]>
+---
+ include/linux/compiler.h | 17 +----------------
+ 1 file changed, 1 insertion(+), 16 deletions(-)
+
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index 681d866efb1e..87c776c3ce73 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -314,29 +314,14 @@ static inline void *offset_to_ptr(const int *off)
+ #endif
+ #ifndef __compiletime_error
+ # define __compiletime_error(message)
+-/*
+- * Sparse complains of variable sized arrays due to the temporary variable in
+- * __compiletime_assert. Unfortunately we can't just expand it out to make
+- * sparse see a constant array size without breaking compiletime_assert on old
+- * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
+- */
+-# ifndef __CHECKER__
+-#  define __compiletime_error_fallback(condition) \
+-	do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
+-# endif
+-#endif
+-#ifndef __compiletime_error_fallback
+-# define __compiletime_error_fallback(condition) do { } while (0)
+ #endif
+
+ #ifdef __OPTIMIZE__
+ # define __compiletime_assert(condition, msg, prefix, suffix)		\
+ 	do {								\
+-		int __cond = !(condition);				\
+ 		extern void prefix ## suffix(void) __compiletime_error(msg); \
+-		if (__cond)						\
++		if (!(condition))					\
+ 			prefix ## suffix();				\
+-		__compiletime_error_fallback(__cond);			\
+ 	} while (0)
+ #else
+ # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
+-- 
+2.17.1
+