kern/136944: [ffs] [lor] bufwait/snaplk (fsync)

[Robert Schulze]

The following reply was made to PR kern/136944; it has been noted by GNATS.

From: Robert Schulze <rs at bytecamp.net>
To: rene at freebsd.org
Cc: bug-followup at freebsd.org
Subject: Re: kern/136944: [ffs] [lor] bufwait/snaplk (fsync)
Date: Fri, 11 Feb 2011 11:18:46 +0100

 Hi,
 
 I can confirm that, too:
 
 lock order reversal:
   1st 0xffffff0019291cc8 ufs (ufs) @ /usr/src/sys/ufs/ffs/ffs_snapshot.c:423
   2nd 0xffffff81ef169978 bufwait (bufwait) @ 
 /usr/src/sys/kern/vfs_bio.c:2636
   3rd 0xffffff00074647e8 ufs (ufs) @ /usr/src/sys/ufs/ffs/ffs_snapshot.c:544
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
 kdb_backtrace() at kdb_backtrace+0x37
 _witness_debugger() at _witness_debugger+0x49
 witness_checkorder() at witness_checkorder+0x7d3
 __lockmgr_args() at __lockmgr_args+0xd0b
 ffs_lock() at ffs_lock+0xac
 VOP_LOCK1_APV() at VOP_LOCK1_APV+0x9b
 _vn_lock() at _vn_lock+0x5d
 ffs_snapshot() at ffs_snapshot+0x1b79
 ffs_mount() at ffs_mount+0x5c5
 vfs_donmount() at vfs_donmount+0xcd4
 nmount() at nmount+0x74
 syscallenter() at syscallenter+0xe5
 syscall() at syscall+0x55
 Xfast_syscall() at Xfast_syscall+0xe2
 --- syscall (378, FreeBSD ELF64, nmount), rip = 0x8007acfdc, rsp = 
 0x7fffffffe9a8, rbp = 0x800a04530 ---
 lock order reversal:
   1st 0xffffff81ef06e6f8 bufwait (bufwait) @ 
 /usr/src/sys/kern/vfs_bio.c:2636
   2nd 0xffffff0015bcc630 snaplk (snaplk) @ 
 /usr/src/sys/ufs/ffs/ffs_snapshot.c:2223
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
 kdb_backtrace() at kdb_backtrace+0x37
 _witness_debugger() at _witness_debugger+0x49
 witness_checkorder() at witness_checkorder+0x7d3
 __lockmgr_args() at __lockmgr_args+0xd0b
 ffs_copyonwrite() at ffs_copyonwrite+0x161
 ffs_geom_strategy() at ffs_geom_strategy+0x159
 bufwrite() at bufwrite+0xff
 ffs_sbupdate() at ffs_sbupdate+0x94
 ffs_sync() at ffs_sync+0x489
 sync_fsync() at sync_fsync+0x136
 VOP_FSYNC_APV() at VOP_FSYNC_APV+0xb5
 sync_vnode() at sync_vnode+0x143
 sched_sync() at sched_sync+0x1c6
 fork_exit() at fork_exit+0x12a
 fork_trampoline() at fork_trampoline+0xe
 --- trap 0, rip = 0, rsp = 0xffffff8245289cf0, rbp = 0 ---
 lock order reversal:
   1st 0xffffff0015bcc630 snaplk (snaplk) @ /usr/src/sys/kern/vfs_vnops.c:296
   2nd 0xffffff0019291cc8 ufs (ufs) @ 
 /usr/src/sys/ufs/ffs/ffs_snapshot.c:1587
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
 kdb_backtrace() at kdb_backtrace+0x37
 _witness_debugger() at _witness_debugger+0x49
 witness_checkorder() at witness_checkorder+0x7d3
 __lockmgr_args() at __lockmgr_args+0xd0b
 ffs_snapremove() at ffs_snapremove+0xe2
 softdep_releasefile() at softdep_releasefile+0x133
 ufs_inactive() at ufs_inactive+0x153
 VOP_INACTIVE_APV() at VOP_INACTIVE_APV+0xb9
 vinactive() at vinactive+0x89
 vputx() at vputx+0x3c6
 vn_close() at vn_close+0x10b
 vn_closefile() at vn_closefile+0x51
 _fdrop() at _fdrop+0x20
 closef() at closef+0x58
 kern_close() at kern_close+0xff
 syscallenter() at syscallenter+0xe5
 syscall() at syscall+0x55
 Xfast_syscall() at Xfast_syscall+0xe2
 --- syscall (6, FreeBSD ELF64, close), rip = 0x800844b1c, rsp = 
 0x7fffffffe9a8, rbp = 0 ---
 
 this was after hot-resetting, maybe due to a background fsck.
 
 with kind regards,
 Robert Schulze