Re: backtrace on current..

On Wed, May 1, 2019 at 5:18 AM Michelle Sullivan <michelle_at_sorbs.net> wrote:
>
> FYI - newly installed:
>
> lock order reversal:
>   1st 0xfffff80004f77608 ufs (ufs) _at_ /usr/src/sys/kern/vfs_lookup.c:713
>   2nd 0xfffffe000080edc0 bufwait (bufwait) _at_
> /usr/src/sys/ufs/ffs/ffs_vnops.c:283
>   3rd 0xfffff80006aff248 ufs (ufs) _at_ /usr/src/sys/kern/vfs_subr.c:2598
> stack backtrace:
> #0 0xffffffff80c48773 at witness_debugger+0x73
> #1 0xffffffff80c484bd at witness_checkorder+0xa7d
> #2 0xffffffff80bb45dd at lockmgr_xlock_hard+0x6d
> #3 0xffffffff80bb505e at __lockmgr_args+0x5fe
> #4 0xffffffff80ef4365 at ffs_lock+0xa5
> #5 0xffffffff81236d93 at VOP_LOCK1_APV+0x63
> #6 0xffffffff80cc3715 at _vn_lock+0x65
> #7 0xffffffff80cb1ee6 at vget+0x66
> #8 0xffffffff80ca3fcc at vfs_hash_get+0xcc
> #9 0xffffffff80eefc4f at ffs_vgetf+0x3f
> #10 0xffffffff80ee5a32 at softdep_sync_buf+0xb62
> #11 0xffffffff80ef5124 at ffs_syncvnode+0x234
> #12 0xffffffff80ecad66 at ffs_truncate+0x716
> #13 0xffffffff80efc909 at ufs_direnter+0x609
> #14 0xffffffff80f055dd at ufs_makeinode+0x5fd
> #15 0xffffffff80f01544 at ufs_create+0x34
> #16 0xffffffff81234b30 at VOP_CREATE_APV+0x60
> #17 0xffffffff80cc301f at vn_open_cred+0x2cf

That particular lock-order reversal is well-known.  It's both harmless
and difficult to fix, which is why nobody's fixed it yet.
-Alan