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x86: Fix mwait_play_dead() faulting on mwait-incapable cpus

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A logic error in mwait_play_dead() causes the kernel to use
mwait even on cpus which don't support it, such as KVM virtual
cpus.

Introduced by:

  349c004e3d: x86: A fast way to check capabilities of the current cpu

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=36222
Reported-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1306758237-9327-1-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Avi Kivity 2011-05-30 08:23:57 -04:00 committed by Ingo Molnar
parent 598e887d8b
commit 4f3c125c74
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kernel/smpboot.c
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@ -1332,7 +1332,7 @@ static inline void mwait_play_dead(void)
void *mwait_ptr;
struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info);
if (!this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c))
if (!(this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c)))
return;
if (!this_cpu_has(X86_FEATURE_CLFLSH))
return;