From a38a44c1a93078fc5fadc4ac2df8dea4697069e2 Mon Sep 17 00:00:00 2001 From: Andrew Morton <akpm@osdl.org> Date: Wed, 6 Dec 2006 20:38:16 -0800 Subject: [PATCH] [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> --- arch/i386/kernel/smp.c | 4 ++++ arch/x86_64/kernel/smp.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c index 31e5c6573aae..9827cf927ecb 100644 --- a/arch/i386/kernel/smp.c +++ b/arch/i386/kernel/smp.c @@ -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); diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c index 9f74c883568c..32f4d7e2a060 100644 --- a/arch/x86_64/kernel/smp.c +++ b/arch/x86_64/kernel/smp.c @@ -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); -- GitLab