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authorAndi Kleen <ak@suse.de>2006-11-14 10:57:46 -0500
committerAndi Kleen <andi@basil.nowhere.org>2006-11-14 10:57:46 -0500
commit9446868b5383eb87f76b2d4389dea4bb968a6657 (patch)
treed253d9a0ae99c77f43ca271019fcbdbfd349b665 /arch
parent8c131af1db510793f87dc43edbc8950a35370df3 (diff)
[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')
-rw-r--r--arch/x86_64/kernel/process.c3
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)
88 88
89static void __exit_idle(void) 89static void __exit_idle(void)
90{ 90{
91 if (read_pda(isidle) == 0) 91 if (test_and_clear_bit_pda(0, isidle) == 0)
92 return; 92 return;
93 write_pda(isidle, 0);
94 atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL); 93 atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
95} 94}
96 95