Messages in this thread Patch in this message | | | Date | Thu, 27 Apr 2006 12:55:51 -0500 | From | Corey Minyard <> | Subject | [PATCH] x86_64: add nmi_exit to die_nmi |
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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()?
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"); }
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 0ebb281..872ddfc 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -472,6 +472,7 @@ void __kprobes die_nmi(char *str, struct panic("nmi watchdog"); printk("console shuts up ...\n"); oops_end(flags); + nmi_exit(); do_exit(SIGSEGV); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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