Date: Tue, 5 Nov 2013 17:45:19 GMT From: "Edward O'Callaghan" <eocallaghan@alterapraxis.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/183689: [lock order reversal] when umounting a ZFS disk. Message-ID: <201311051745.rA5HjJOK038247@oldred.freebsd.org> Resent-Message-ID: <201311051750.rA5Ho1nF079616@freefall.freebsd.org>
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>Number: 183689 >Category: kern >Synopsis: [lock order reversal] when umounting a ZFS disk. >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Nov 05 17:50:00 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Edward O'Callaghan >Release: ~ FreeBSD 10.0-BETA3 >Organization: Altera Praxis Pty Ltd >Environment: FreeBSD acid.alterapraxis.com 11.0-CURRENT FreeBSD 11.0-CURRENT #3 r257709: Tue Nov 5 16:40:15 EST 2013 root@acid.alterapraxis.com:/usr/obj/usr/src/sys/GENERIC amd64 >Description: On reboot when unmounting a ZFS root there seems to be a lock order reversal between, 1st 0xfffff800145fd7c8 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1237 2nd 0xfffff800142ac240 devfs (devfs) @ /usr/src/sys/kern/vfs_subr.c:210 Since I can't understand the insane locking in vfs_mount.c:1237 I have no idea how to fix this. ---- Waiting (max 60 seconds) for system process `syncer' to stop...Syncing disks, vnodes remaining...0 0 0 0 0 0 0 done Waiting (max 60 seconds) for system process `bufdaemon' to stop...done All buffers synced. lock order reversal: 1st 0xfffff800145fd7c8 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:1237 2nd 0xfffff800142ac240 devfs (devfs) @ /usr/src/sys/kern/vfs_subr.c:2101 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe084d734460 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe084d734510 witness_checkorder() at witness_checkorder+0xd23/frame 0xfffffe084d7345a0 __lockmgr_args() at __lockmgr_args+0x86c/frame 0xfffffe084d7346d0 vop_stdlock() at vop_stdlock+0x3c/frame 0xfffffe084d7346f0 VOP_LOCK1_APV() at VOP_LOCK1_APV+0xf5/frame 0xfffffe084d734720 _vn_lock() at _vn_lock+0xab/frame 0xfffffe084d734790 vget() at vget+0x70/frame 0xfffffe084d7347e0 devfs_allocv() at devfs_allocv+0xfd/frame 0xfffffe084d734830 devfs_root() at devfs_root+0x43/frame 0xfffffe084d734860 dounmount() at dounmount+0x35a/frame 0xfffffe084d7348e0 vfs_unmountall() at vfs_unmountall+0x61/frame 0xfffffe084d734910 kern_reboot() at kern_reboot+0x548/frame 0xfffffe084d734980 sys_reboot() at sys_reboot+0x58/frame 0xfffffe084d7349a0 amd64_syscall() at amd64_syscall+0x265/frame 0xfffffe084d734ab0 Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe084d734ab0 --- syscall (55, FreeBSD ELF64, sys_reboot), rip = 0x80085f3fc, rsp = 0x7fffffffda38, rbp = 0x7fffffffdba0 --- --- >How-To-Repeat: reboot >Fix: N/A. >Release-Note: >Audit-Trail: >Unformatted:
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