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[PATCH] smp_call_function_single() check that local interrupts are enabled 

smp_call_function_single() can deadlock if the caller disabled local
interrupts (the target CPU could be spinning on call_lock).  Check for that.

Why on earth do these functions use spin_lock_bh()??

Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton 2006-12-06 20:38:16 -08:00 committed by Linus Torvalds
parent 83df8db9e6
commit a38a44c1a9
2 changed files with 8 additions and 0 deletions
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4
arch/i386/kernel/smp.c
View File

@ -699,6 +699,10 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
put_cpu(); put_cpu();
return -EBUSY; return -EBUSY;
} }
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock); spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait); __smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock); spin_unlock_bh(&call_lock);

4
arch/x86_64/kernel/smp.c
View File

@ -379,6 +379,10 @@ int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
put_cpu(); put_cpu();
return 0; return 0;
} }
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock); spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait); __smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock); spin_unlock_bh(&call_lock);