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Commit a38a44c1 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 83df8db9

arch/i386/kernel/smp.c

+4 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86_64/kernel/smp.c

+4 −0
Original line number Diff line number Diff line
@@ -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);