sched/x86/smp: Do not enable IRQs over calibrate_delay()
Commit-ID: bc758133ed73d4b06952bec21da23e28e62bf3ba Gitweb: http://git.kernel.org/tip/bc758133ed73d4b06952bec21da23e28e62bf3ba Author: Peter Zijlstra <[email protected]> AuthorDate: Mon, 26 Mar 2012 13:16:15 +0200 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 27 Mar 2012 14:50:10 +0200
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 <[email protected]>
Cc Linus Torvalds <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
--- arch/x86/kernel/smpboot.c | 5 ----- 1 files changed, 0 insertions(+), 5 deletions(-)
arch/x86/kernel/smpboot.c +0 -5
@@ -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);/*