Date: Thu, 23 Jun 2011 13:30:05 -0400 From: Tim Stewart <tim@stoo.org> To: freebsd-bugs@freebsd.org Subject: ``Fatal double fault'' when running nightly jobs, perhaps ZFS-related Message-ID: <4E03781D.1090504@stoo.org>
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Hello, I have a FreeBSD 8.2-RELEASE-p2 system that uses ZFS, including booting. The kernel is locally compiled and is just the GENERIC configuration with DTrace enabled and a MFI driver patch from the mailing list post at [1]. The system panicked with a ``Fatal double fault'' at 3:09 AM one night (typed in manually from a screenshot, but proofread): Fatal double fault rip = 0xffffffff805d3eeb rsp = 0xffffff848585b000 rbp = 0xffffff848585b020 cpuid = 0; apic id = 20 panic: double fault cpuid = 0 KDB: stack backtrace #0 0xffffffff80618d3e at kdb_backtrace+0x5e #1 0xffffffff805e4d47 at panic+0x187 #2 0xffffffff808dc834 at dblfault_handler+0xa4 #3 0xffffffff808c53ad at Xdblfault+0xad Uptime: 3d11h11m37s Cannot dump. Device not defined or unavailable. Automatic reboot in 15 seconds - press a key on the console to abort Sleeping thread (tid 100141, pid 5) owns a non-sleepable lock It seems likely that the activity that prompted the fault is related to the nightly periodic jobs. Others have suggested that it may be related to /etc/periodic/security/100.chksetuid (see [2] and [3]), as it does a find on every filesystem not marked as `nosuid.' Indeed, I have a ZFS dataset containing 71+ million files that (at the time) was not marked as nosuid. I have not been able to replicate the issue since and it has only happened once. I have set `setuid=off' on the large ZFS dataset so that 100.chksetuid will no longer traverse it every night. Any clue as to what is happening here? I don't have a kernel core dump since I'm using ZFS for swap, though I can change this if it helps troubleshoot the issue in the event of another crash. Thanks for any help you can provide, -- -TimS Tim Stewart References: [1] http://lists.freebsd.org/pipermail/freebsd-scsi/2011-March/004839.html [2] http://lists.freebsd.org/pipermail/freebsd-bugs/2011-March/043781.html [3] http://forums.freebsd.org/showthread.php?t=23919
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