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On Sun, May 01, 2005 at 10:04:28AM -0700, Linux Kernel wrote: > tree 6adb8d33585f8eee20794827c79e40991aeeaee5 > parent fd51f666fa591294bd7462447512666e61c56ea0 > author Jack F Vogel <jfv@bluesong.net> Sun, 01 May 2005 22:58:48 -0700 > committer Linus Torvalds <torvalds@ppc970.osdl.org> Sun, 01 May 2005 22:58:48 -0700 > > [PATCH] check nmi watchdog is broken > > A bug against an xSeries system showed up recently noting that the > check_nmi_watchdog() test was failing. > > I have been investigating it and discovered in both i386 and x86_64 the > recent change to the routine to use the cpu_callin_map has uncovered a > problem. Prior to that change, on an SMP box, the test was trivally > passing because all cpu's were found to not yet be online, but now with the > callin_map they are discovered, it goes on to test the counter and they > have not yet begun to increment, so it announces a CPU is stuck and bails > out. > > On all the systems I have access to test, the announcement of failure is > also bougs... by the time you can login and check /proc/interrupts, the > NMI count is happily incrementing on all CPUs. Its just that the test is > being done too early. > > I have tried moving the call to the test around a bit, and it was always > too early. I finally hit on this proposed solution, it delays the routine > via a late_initcall(), seems like the right solution to me. My EM64T Dell Precision 470 seems to have problems both before and after this change, though the behaviour changes. With -rc3.. testing NMI watchdog ... CPU#1: NMI appears to be stuck (0)! With -rc4... Testing NMI watchdog ... CPU#4: NMI appears to be stuck (0)! The CPU #'s are consistent across reboots (Ie, they're always the same). Though the rc4 behaviour seems odd, as my CPUs are numbered 0-3. Bill (Cc'd) also reports that with -rc4, he sees around a 10 second delay when it does that 'Testing NMI watchdog' message. Dave - 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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