i386: fix a hang on stuck nmi watchdog
authorDaniel Walker <dwalker@mvista.com>
Thu, 6 Sep 2007 14:59:54 +0000 (16:59 +0200)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 11 Sep 2007 01:57:47 +0000 (18:57 -0700)
In the case when an nmi gets stucks the endflag stays equal to zero.
This causes the busy looping on other cpus to continue, even though the
nmi test is done.

On my machine with out the change below the system would hang right
after check_nmi_watchdog().  The change below just sets endflag prior to
checking if the test was successful or not.

Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/i386/kernel/nmi.c

index 8c1c965eb2a8e4b6c54d0bb7db320303d6844144..c7227e2180f850bde4a04de8a0e4417045bd6be2 100644 (file)
@@ -115,12 +115,12 @@ static int __init check_nmi_watchdog(void)
                        atomic_dec(&nmi_active);
                }
        }
+       endflag = 1;
        if (!atomic_read(&nmi_active)) {
                kfree(prev_nmi_count);
                atomic_set(&nmi_active, -1);
                return -1;
        }
-       endflag = 1;
        printk("OK.\n");
 
        /* now that we know it works we can reduce NMI frequency to