Messages in this thread Patch in this message |  | | From | Steven Noonan <> | Subject | [PATCH v2] compiler/gcc4: make quirk for asm_volatile_goto unconditional | Date | Wed, 12 Feb 2014 23:01:07 -0800 |
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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.
[1] http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Signed-off-by: Steven Noonan <steven@uplinklabs.net> ---
v2: Adding stable@vger.kernel.org to Cc.
include/linux/compiler-gcc4.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index ded4299..2507fd2 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 -- 1.8.5.4
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