diff options
| author | Steven Noonan <steven@uplinklabs.net> | 2014-02-12 23:01:07 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-22 13:32:29 -0800 |
| commit | a6ad68bc9fd3159cfb3495d4f96b2d20bb625fad (patch) | |
| tree | d9c6adae2356be943d6108f857834e7d7dead258 | |
| parent | 1f25819485fdaee53cc5b8ec96a44a440a63cf46 (diff) | |
compiler/gcc4: Make quirk for asm_volatile_goto() unconditional
commit a9f180345f5378ac87d80ed0bea55ba421d83859 upstream.
I started noticing problems with KVM guest destruction on Linux
3.12+, where guest memory wasn't being cleaned up. I bisected it
down to the commit introducing the new 'asm goto'-based atomics,
and found this quirk was later applied to those.
Unfortunately, even with GCC 4.8.2 (which ostensibly fixed the
known 'asm goto' bug) I am still getting some kind of
miscompilation. If I enable the asm_volatile_goto quirk for my
compiler, KVM guests are destroyed correctly and the memory is
cleaned up.
So make the quirk unconditional for now, until bug is found
and fixed.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/1392274867-15236-1-git-send-email-steven@uplinklabs.net
Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/compiler-gcc4.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index ded429966c1f..2507fd2a1eb4 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -75,11 +75,7 @@ * * (asm goto is automatically volatile - the naming reflects this.) */ -#if GCC_VERSION <= 40801 -# define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) -#else -# define asm_volatile_goto(x...) do { asm goto(x); } while (0) -#endif +#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) #ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP #if GCC_VERSION >= 40400 |