From 8b1ffe9550e71224c43d8c754245bd76f4ea9bb8 Mon Sep 17 00:00:00 2001 From: Corey Minyard Date: Mon, 8 May 2006 15:17:25 +0200 Subject: [PATCH] [PATCH] x86_64: add nmi_exit to die_nmi Playing with NMI watchdog on x86_64, I discovered that it didn't do what I expected. It always panic-ed, even when it didn't happen from interrupt context. This patch solves that problem for me. Also, in this case, do_exit() will be called with interrupts disabled, I believe. Would it be wise to also call local_irq_enable() after nmi_exit()? [Yes I added it -AK] Currently, on x86_64, any NMI watchdog timeout will cause a panic because the irq count will always be set to be in an interrupt when do_exit() is called from die_nmi(). If we add nmi_exit() to the die_nmi() call (since the nmi will never exit "normally") it seems to solve this problem. The following small program can be used to trigger the NMI watchdog to reproduce this: main () { iopl(3); for (;;) asm("cli"); } Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/traps.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 0ebb281aa17..6b87268c5c2 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -472,6 +472,8 @@ void __kprobes die_nmi(char *str, struct pt_regs *regs) panic("nmi watchdog"); printk("console shuts up ...\n"); oops_end(flags); + nmi_exit(); + local_irq_enable(); do_exit(SIGSEGV); } -- 2.41.0