Commit a38a44c1 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 83df8db9
......@@ -699,6 +699,10 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
put_cpu();
return -EBUSY;
}
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock);
......
......@@ -379,6 +379,10 @@ int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
put_cpu();
return 0;
}
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock);
......
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