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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-03-26 13:16:15 +0200
committerIngo Molnar <mingo@kernel.org>2012-03-27 14:50:10 +0200
commitbc758133ed73d4b06952bec21da23e28e62bf3ba (patch)
treec7d2a8cec16533e7d3b3896f9fdc7c0350b8a041 /arch/x86/kernel/smpboot.c
parentsched: Fix compiler warning about declared inline after use (diff)
downloadlinux-bc758133ed73d4b06952bec21da23e28e62bf3ba.tar.xz
linux-bc758133ed73d4b06952bec21da23e28e62bf3ba.zip
sched/x86/smp: Do not enable IRQs over calibrate_delay()
We should not ever enable IRQs until we're fully set up. This opens up a window where interrupts can hit the cpu and interrupts can do wakeups, wakeups need state that isn't set-up yet, in particular this cpu isn't elegible to run tasks, so if any cpu-affine task that got created in CPU_UP_PREPARE manages to get a wakeup, its affinity mask will get broken and we'll run into lots of 'interesting' problems. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-yaezmlbriluh166tfkgni22m@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to '')
-rw-r--r--arch/x86/kernel/smpboot.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 58f78165d308..89571a0c4a49 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -219,14 +219,9 @@ static void __cpuinit smp_callin(void)
* Update loops_per_jiffy in cpu_data. Previous call to
* smp_store_cpu_info() stored a value that is close but not as
* accurate as the value just calculated.
- *
- * Need to enable IRQs because it can take longer and then
- * the NMI watchdog might kill us.
*/
- local_irq_enable();
calibrate_delay();
cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
- local_irq_disable();
pr_debug("Stack at about %p\n", &cpuid);
/*