kern/136945: [ufs] [lor] filedesc structure/ufs (poll)

[Rene Ladan]

2009/7/28 John Baldwin <jhb at freebsd.org>:
> On Tuesday 28 July 2009 10:03:40 am Rene Ladan wrote:
>> 2009/7/28 John Baldwin <jhb at freebsd.org>:
>> > On Monday 27 July 2009 10:00:05 am Rene Ladan wrote:
>> >> The following reply was made to PR kern/136945; it has been noted by
> GNATS.
>> >>
>> >> From: Rene Ladan <rene at freebsd.org>
>> >> To: John Baldwin <jhb at freebsd.org>
>> >> Cc: bug-followup at freebsd.org
>> >> Subject: Re: kern/136945: [ufs] [lor] filedesc structure/ufs (poll)
>> >> Date: Mon, 27 Jul 2009 15:51:15 +0200
>> >>
>> >>  2009/7/27 John Baldwin <jhb at freebsd.org>:
>> >>  > I would actually expect this to be the correct order for these two
>> > locks.=
>> >>   =A0Can
>> >>  > you capture the output of the 'debug.witness.fullgraph' sysctl to a
> file?
>> >>  >
>> >>  Yes, see attachment.  I'm still running the same 8.0-BETA2.
>> >
>> > Hmm, the attachment was eaten by a grue, can you post the file somewhere?
>> >
>> Yes, see ftp://rene-ladan.nl/pub/freebsd/kern_136945.txt
>
> Ok, it looks like it did encounter a UFS -> filedesc order at some point.  Can
> you patch sys/kern/subr_witness.c to add a section to the order_lists[] array
> after the 'ZFS locking list' and before the spin locks list that looks like
> this:
>
>        { "filedesc structure", &lock_class_sx },
>        { "ufs", &lock_class_lockmgr},
>        { NULL, NULL },
>
The LOR seems to be gone, previously it showed up only once right
after booting the system.

But now a new LOR (according to the LOR page) seems pop up:
Trying to mount root from ufs:/dev/ad0s1a
lock order reversal:
 1st 0xffffff0002a4ad80 ufs (ufs) @ /usr/src/sys/ufs/ffs/ffs_vfsops.c:1465
 2nd 0xffffff0002b29a48 filedesc structure (filedesc structure) @
/usr/src/sys/kern/kern_descrip.c:2478
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
_witness_debugger() at _witness_debugger+0x49
witness_checkorder() at witness_checkorder+0x7ea
_sx_xlock() at _sx_xlock+0x44
mountcheckdirs() at mountcheckdirs+0x80
vfs_donmount() at vfs_donmount+0xfbf
kernel_mount() at kernel_mount+0xa1
vfs_mountroot_try() at vfs_mountroot_try+0x177
vfs_mountroot() at vfs_mountroot+0x47d
start_init() at start_init+0x62
fork_exit() at fork_exit+0x12a
fork_trampoline() at fork_trampoline+0xe
--- trap 0, rip = 0, rsp = 0xffffff800001ad30, rbp = 0 ---

The output of `df' and `mount' looks ok.

René