Bug 210906

Summary: [lor] lock order reversal in vfs_mount/vfs_subr under ZFS
Product: Base System Reporter: Paul Armstrong <freebsd>
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: Closed FIXED    
Severity: Affects Only Me CC: amd64, mjg
Priority: ---    
Version: CURRENT   
Hardware: amd64   
OS: Any   

Description Paul Armstrong 2016-07-08 04:50:04 UTC 
lock order reversal:
 1st 0xfffff80004da07c8 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:848
 2nd 0xfffff8000f8535f0 devfs (devfs) @ /usr/src/sys/kern/vfs_subr.c:2523
stack backtrace:
#0 0xffffffff80aae180 at witness_debugger+0x70
#1 0xffffffff80aae074 at witness_checkorder+0xe54
#2 0xffffffff80a26dc2 at __lockmgr_args+0x4c2
#3 0xffffffff80afeebc at vop_stdlock+0x3c
#4 0xffffffff810738ea at VOP_LOCK1_APV+0xda
#5 0xffffffff80b1fc2a at _vn_lock+0x9a
#6 0xffffffff80b10123 at vget+0x63
#7 0xffffffff8092122d at devfs_allocv+0xcd
#8 0xffffffff80920d33 at devfs_root+0x43
#9 0xffffffff80b0746e at vfs_donmount+0x144e
#10 0xffffffff80b05ff2 at sys_nmount+0x72
#11 0xffffffff80f16b2b at amd64_syscall+0x2db
#12 0xffffffff80ef68cb at Xfast_syscall+0xfb

Noticed when stopping a ZFS mounted jail.
11.0 Alpha 6
Comment 1 Paul Armstrong 2016-07-08 04:51:55 UTC 
That should say "noticed when _starting_ a ZFS based jail"