* [tip:x86/asm 24/32] mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction
@ 2017-11-03 3:36 kbuild test robot
2017-11-03 15:50 ` Josh Poimboeuf
0 siblings, 1 reply; 4+ messages in thread
From: kbuild test robot @ 2017-11-03 3:36 UTC (permalink / raw)
To: Andy Lutomirski
Cc: kbuild-all, linux-kernel, tipbuild, Ingo Molnar, Borislav Petkov
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tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/asm
head: 1e4c4f610f774df6088d7c065b2dd4d22adba698
commit: da51da189a24bb9b7e2d5a123be096e51a4695a5 [24/32] x86/entry/64: Pass SP0 directly to load_sp0()
config: x86_64-randconfig-in0-11031034 (attached as .config)
compiler: gcc-4.6 (Debian 4.6.4-7) 4.6.4
reproduce:
git checkout da51da189a24bb9b7e2d5a123be096e51a4695a5
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
>> mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [tip:x86/asm 24/32] mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction 2017-11-03 3:36 [tip:x86/asm 24/32] mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction kbuild test robot @ 2017-11-03 15:50 ` Josh Poimboeuf 2017-11-03 22:19 ` [PATCH] objtool: Prevent GCC from merging annotate_unreachable(), take 2 Josh Poimboeuf 0 siblings, 1 reply; 4+ messages in thread From: Josh Poimboeuf @ 2017-11-03 15:50 UTC (permalink / raw) To: kbuild test robot Cc: Andy Lutomirski, kbuild-all, linux-kernel, tipbuild, Ingo Molnar, Borislav Petkov On Fri, Nov 03, 2017 at 11:36:50AM +0800, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/asm > head: 1e4c4f610f774df6088d7c065b2dd4d22adba698 > commit: da51da189a24bb9b7e2d5a123be096e51a4695a5 [24/32] x86/entry/64: Pass SP0 directly to load_sp0() > config: x86_64-randconfig-in0-11031034 (attached as .config) > compiler: gcc-4.6 (Debian 4.6.4-7) 4.6.4 > reproduce: > git checkout da51da189a24bb9b7e2d5a123be096e51a4695a5 > # save the attached .config to linux build tree > make ARCH=x86_64 > > All warnings (new ones prefixed by >>): > > >> mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction I've got a fix for this one coming shortly. -- Josh ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] objtool: Prevent GCC from merging annotate_unreachable(), take 2 2017-11-03 15:50 ` Josh Poimboeuf @ 2017-11-03 22:19 ` Josh Poimboeuf 2017-11-04 22:31 ` [tip:core/urgent] " tip-bot for Josh Poimboeuf 0 siblings, 1 reply; 4+ messages in thread From: Josh Poimboeuf @ 2017-11-03 22:19 UTC (permalink / raw) To: x86 Cc: Andy Lutomirski, kbuild-all, linux-kernel, tipbuild, Ingo Molnar, Borislav Petkov, kbuild test robot This fixes the following warning with GCC 4.6: mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction The problem is that the compiler merged identical annotate_unreachable() inline asm blocks, resulting in a missing 'unreachable' annotation. This problem happened before, and was partially fixed with: 3d1e236022cc ("objtool: Prevent GCC from merging annotate_unreachable()") That commit tried to ensure that each instance of the annotate_unreachable() inline asm statement has a unique label. It used the __LINE__ macro to generate the label number. However, even the line number isn't necessarily unique when used in an inline function with multiple callers (in this case, __alloc_pages_node()'s use of VM_BUG_ON). Reported-by: kbuild test robot <fengguang.wu@intel.com> Fixes: 3d1e236022cc ("objtool: Prevent GCC from merging annotate_unreachable()") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- include/linux/compiler.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index e95a2631e545..e9fe95b138cf 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -190,13 +190,13 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, asm("%c0:\n\t" \ ".pushsection .discard.reachable\n\t" \ ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__LINE__)); \ + ".popsection\n\t" : : "i" (__COUNTER__)); \ }) #define annotate_unreachable() ({ \ asm("%c0:\n\t" \ ".pushsection .discard.unreachable\n\t" \ ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__LINE__)); \ + ".popsection\n\t" : : "i" (__COUNTER__)); \ }) #define ASM_UNREACHABLE \ "999:\n\t" \ -- 2.13.6 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [tip:core/urgent] objtool: Prevent GCC from merging annotate_unreachable(), take 2 2017-11-03 22:19 ` [PATCH] objtool: Prevent GCC from merging annotate_unreachable(), take 2 Josh Poimboeuf @ 2017-11-04 22:31 ` tip-bot for Josh Poimboeuf 0 siblings, 0 replies; 4+ messages in thread From: tip-bot for Josh Poimboeuf @ 2017-11-04 22:31 UTC (permalink / raw) To: linux-tip-commits Cc: peterz, hpa, jpoimboe, fengguang.wu, mingo, tglx, bp, torvalds, linux-kernel, luto Commit-ID: ec1e1b6109171d1890a437481c35b2b56d2327b8 Gitweb: https://git.kernel.org/tip/ec1e1b6109171d1890a437481c35b2b56d2327b8 Author: Josh Poimboeuf <jpoimboe@redhat.com> AuthorDate: Fri, 3 Nov 2017 17:19:41 -0500 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Sat, 4 Nov 2017 15:03:39 +0100 objtool: Prevent GCC from merging annotate_unreachable(), take 2 This fixes the following warning with GCC 4.6: mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction The problem is that the compiler merged identical annotate_unreachable() inline asm blocks, resulting in a missing 'unreachable' annotation. This problem happened before, and was partially fixed with: 3d1e236022cc ("objtool: Prevent GCC from merging annotate_unreachable()") That commit tried to ensure that each instance of the annotate_unreachable() inline asm statement has a unique label. It used the __LINE__ macro to generate the label number. However, even the line number isn't necessarily unique when used in an inline function with multiple callers (in this case, __alloc_pages_node()'s use of VM_BUG_ON). Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kbuild-all@01.org Cc: tipbuild@zytor.com Fixes: 3d1e236022cc ("objtool: Prevent GCC from merging annotate_unreachable()") Link: http://lkml.kernel.org/r/20171103221941.cajpwszir7ujxyc4@treble Signed-off-by: Ingo Molnar <mingo@kernel.org> --- include/linux/compiler.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index fd8697a..2027104 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -191,13 +191,13 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, asm("%c0:\n\t" \ ".pushsection .discard.reachable\n\t" \ ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__LINE__)); \ + ".popsection\n\t" : : "i" (__COUNTER__)); \ }) #define annotate_unreachable() ({ \ asm("%c0:\n\t" \ ".pushsection .discard.unreachable\n\t" \ ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__LINE__)); \ + ".popsection\n\t" : : "i" (__COUNTER__)); \ }) #define ASM_UNREACHABLE \ "999:\n\t" \ ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-11-04 22:36 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-11-03 3:36 [tip:x86/asm 24/32] mm/migrate.o: warning: objtool: migrate_misplaced_transhuge_page()+0x71: unreachable instruction kbuild test robot 2017-11-03 15:50 ` Josh Poimboeuf 2017-11-03 22:19 ` [PATCH] objtool: Prevent GCC from merging annotate_unreachable(), take 2 Josh Poimboeuf 2017-11-04 22:31 ` [tip:core/urgent] " tip-bot for Josh Poimboeuf
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