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| author |   Andi Kleen <ak@suse.de> | 2006-11-14 16:57:46 +0100 |
|---|---|---|
| committer |   Andi Kleen <andi@basil.nowhere.org> | 2006-11-14 16:57:46 +0100 |
| commit | 9446868b5383eb87f76b2d4389dea4bb968a6657 (patch) | |
| tree | d253d9a0ae99c77f43ca271019fcbdbfd349b665 /arch/x86_64 | |
| parent | [PATCH] x86-64: Fix vgetcpu when CONFIG_HOTPLUG_CPU is disabled (diff) | |
| download | linux-dev-9446868b5383eb87f76b2d4389dea4bb968a6657.tar.xz linux-dev-9446868b5383eb87f76b2d4389dea4bb968a6657.zip | |
[PATCH] x86-64: Fix race in exit_idle
When another interrupt happens in exit_idle the exit idle notifier
could be called an incorrect number of times.
Add a test_and_clear_bit_pda and use it handle the bit
atomically against interrupts to avoid this.
Pointed out by Stephane Eranian
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64')
| -rw-r--r-- | arch/x86_64/kernel/process.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 49f7fac6229e..f6226055d53d 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -88,9 +88,8 @@ void enter_idle(void) static void __exit_idle(void) { - if (read_pda(isidle) == 0) + if (test_and_clear_bit_pda(0, isidle) == 0) return; - write_pda(isidle, 0); atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL); } |