]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
compiler/gcc4: Make quirk for asm_volatile_goto() unconditional
authorSteven Noonan <steven@uplinklabs.net>
Thu, 13 Feb 2014 07:01:07 +0000 (23:01 -0800)
committerIngo Molnar <mingo@kernel.org>
Thu, 13 Feb 2014 11:34:05 +0000 (12:34 +0100)
commita9f180345f5378ac87d80ed0bea55ba421d83859
treef0b821e2aa4f83afffd450929a75f544993dd20d
parent569d6557ab957d6ae7e97a46ae669174be4189e6
compiler/gcc4: Make quirk for asm_volatile_goto() unconditional

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>
Cc: <stable@vger.kernel.org>
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>
include/linux/compiler-gcc4.h