Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 20 Jan 2014 07:36:15 -0800
From:      David Wolfskill <david@catwhisker.org>
To:        current@freebsd.org
Subject:   panic: mtx_lock_spin: recursed on non-recursive mutex uart_hwmtx...
Message-ID:  <20140120153615.GS1789@albert.catwhisker.org>

next in thread | raw e-mail | index | archive | help

--IUSVF+LtaR4kWxuH
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

I saw this on my "build machine" after updating the "head" slice from:

FreeBSD 11.0-CURRENT #1387  r260875M/260877:1100005: Sun Jan 19 11:57:25 PS=
T 2014     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/sys/GENERIC=
  i386

to

FreeBSD 11.0-CURRENT #1388  r260904M/260904:1100005: Mon Jan 20 06:25:53 PS=
T 2014     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/sys/GENERIC=
  i386


A bit of context:  On this machine and my laptop, it is my practice to perf=
orm the following on a daily basis:
* Ensure the machine is booted from slice 1 (stable/9).
* Update the ports tree.
* Update the source tree.
* Start fetching any ports that are to be updated.
* Update stable/9.
* Reboot (staying on slice 1 -- stable/9).
* Update the installed ports that warrant it ("portmaster -da --index").
* Update the sources on slice 3 (stable/10).
* Remove old libraries for stable/9 ("make delete-old-libs").
* Reboot to slice 3 (stable/10).
* Update stable/10.
* Reboot (staying on slice 3 -- stable/10).
* Update the sources on slice 4 (head).
* Remove old libraries for stable/10 ("make delete-old-libs").
* Reboot to slice 4 (head)
* Update head.
* Reboot (staying on slice 4 -- head).
* Remove old libraries for head ("make delete-old-libs").

[If a given slice didn't have source updates, I don't try to rebuild
FreeBSD on it, though.]

For my laptop, I then reboot to slice 1 (usually; sometimes slice
3, especially if there were no source updates for stable/9).  For
the build machine, I set the default boot slice back to 1, then issue
"shutdown -p now" to shut it off until just before midnight.

Today, there were a couple of perturbations from the above:
* The only update for stable/10 I had was:
  U    /S3/usr/src/release/doc/en_US.ISO8859-1/errata/article.xml

  so I decided that didn't warrant rebuilding FreeBSD stable/10.

* The panic in the Subject line -- only on the build machine.

Here's what I see (cut/paste) on serial console:

=2E..
Jan 20 07:02:12 freebeast shutdown: power-down by david:=20
Stopping cron.
Waiting for PIDS: 1090.
Stopping sshd.
Waiting for PIDS: 1080.
Stopping rsyncd.
Waiting for PIDS: 1057.
Stopping powerd.
Waiting for PIDS: 1042.
sysctl: dev.cpu.0.freq=3D3600: Device not configured
Stopping ntpd.
Waiting for PIDS: 1039.
Stopping lpd.
Waiting for PIDS: 1018.
Stopping lockd.
Waiting for PIDS: 1001.
Stopping statd.
Waiting for PIDS: 998.
Stopping nfsd.
Waiting for PIDS: 994 995.
Stopping mountd.
Waiting for PIDS: 992.
Stopping casperd.
Waiting for PIDS: 951.
Stopping amd.
Waiting for PIDS: 943.
Stopping ypbind.
Stopping rpcbind.
Waiting for PIDS: 916, 916.
Stopping devd.
Writing entropy file:.
Terminated
=2E
Jan 20 07:02:16 freebeast syslogd: exiting on signal 15
Waiting (max 60 seconds) for system process `vnlru' to stop...done
Waiting (max 60 seconds) for system process `syncer' to stop...
Syncing disks, vnodes remaining...2 4 4 4 3 3 3 2 1 1 0 0 0 0 done
Waiting (max 60 seconds) for system process `bufdaemon' to stop...done
All buffers synced.
lock order reversal:
 1st 0xc7336c68 ufs (ufs) @ /usr/src/sys/kern/vfs_mount.c:1237
 2nd 0xc76846dc devfs (devfs) @ /usr/src/sys/ufs/ffs/ffs_vfsops.c:1412
KDB: stack backtrace:
db_trace_self_wrapper(c112d57c,a3231,e1fb9888,c0b1bfe7,1,...) at db_trace_s=
elf_wrapper+0x2d/frame 0xe1fb9828
kdb_backtrace(c1131131,c76846dc,c1124024,c6dad2d0,c1162dc1,...) at kdb_back=
trace+0x30/frame 0xe1fb9890
witness_checkorder(c76846dc,9,c1162dc1,584,0,...) at witness_checkorder+0xc=
8a/frame 0xe1fb98e0
__lockmgr_args(c76846dc,80400,c76846fc,0,0,0,c1162dc1,584) at __lockmgr_arg=
s+0x844/frame 0xe1fb99b4
vop_stdlock(e1fb9a28,c6dad3a0,c6dad408,c169bc38,e1fb9a4c,...) at vop_stdloc=
k+0x4d/frame 0xe1fb99e4
VOP_LOCK1_APV(c13828dc,e1fb9a28,0,0,c13cded0,...) at VOP_LOCK1_APV+0x104/fr=
ame 0xe1fb9a10
_vn_lock(c76846a8,80400,c1162dc1,584,c1393aac,...) at _vn_lock+0xa1/frame 0=
xe1fb9a50
ffs_flushfiles(c753f000,a,c6f0a310,e1fb9b38,c0d416e3,...) at ffs_flushfiles=
+0x14c/frame 0xe1fb9a9c
softdep_flushfiles(c753f000,2,c6f0a310,0,0,...) at softdep_flushfiles+0x6e/=
frame 0xe1fb9af0
ffs_unmount(c753f000,80000,e1fb9b70,518,c6f0a310,...) at ffs_unmount+0x194/=
frame 0xe1fb9b38
dounmount(c753f000,80000,c6f0a310,0,e1db3eb0,...) at dounmount+0x4dc/frame =
0xe1fb9b98
vfs_unmountall(e1db4058,0,c112895a,144,c6d8b1a0,...) at vfs_unmountall+0x4e=
/frame 0xe1fb9bb8
kern_reboot(4008,0,c112895a,c3,0,...) at kern_reboot+0x5af/frame 0xe1fb9c20
sys_reboot(c6f0a310,e1fb9cc8,14,c112b5b7,7a2,...) at sys_reboot+0x6f/frame =
0xe1fb9c40
syscall(e1fb9d08) at syscall+0x2de/frame 0xe1fb9cfc
Xint0x80_syscall() at Xint0x80_syscall+0x21/frame 0xe1fb9cfc
--- syscall (55, FreeBSD ELF32, sys_reboot), eip =3D 0x805a9df, esp =3D 0xb=
fbfd88c, ebp =3D 0xbfbfd960 ---
Uptime: 4m28s
panic: mtx_lock_spin: recursed on non-recursive mutex uart_hwmtx @ /usr/src=
/sys/dev/uart/uart_cpu.h:94

cpuid =3D 0
KDB: stack backtrace:
db_trace_self_wrapper(c112d57c,2f727375,2f637273,2f737973,2f766564,...) at =
db_trace_self_wrapper+0x2d/frame 0xe1fb9a60
kdb_backtrace(c12ec1f3,0,c11269a2,e1fb9b38,e1fb9b08,...) at kdb_backtrace+0=
x30/frame 0xe1fb9ac8
vpanic(c140d0c8,100,c11269a2,e1fb9b38,e1fb9b38,...) at vpanic+0x11f/frame 0=
xe1fb9b08
kassert_panic(c11269a2,c10f66d8,c10f6758,5e,8,...) at kassert_panic+0xea/fr=
ame 0xe1fb9b2c
__mtx_lock_spin_flags(c7291830,0,c10f6758,5e,c137d684,...) at __mtx_lock_sp=
in_flags+0x190/frame 0xe1fb9b5c
ns8250_bus_grab(c7291800,c7062b28,c137d684,5e,c140b9a4,...) at ns8250_bus_g=
rab+0x40/frame 0xe1fb9b78
uart_grab(c13fd070) at uart_grab+0x83/frame 0xe1fb9b9c
uart_cngrab(c137d69c,88888889,e1fb9c20,c0ac7d43,c1128e43,...) at uart_cngra=
b+0x12/frame 0xe1fb9ba8
cngrab(c1128e43,1c,c112895a,144,c6d8b1a0,...) at cngrab+0x33/frame 0xe1fb9b=
b8
kern_reboot(4008,0,c112895a,c3,0,...) at kern_reboot+0x6d3/frame 0xe1fb9c20
sys_reboot(c6f0a310,e1fb9cc8,14,c112b5b7,7a2,...) at sys_reboot+0x6f/frame =
0xe1fb9c40
syscall(e1fb9d08) at syscall+0x2de/frame 0xe1fb9cfc
Xint0x80_syscall() at Xint0x80_syscall+0x21/frame 0xe1fb9cfc
--- syscall (55, FreeBSD ELF32, sys_reboot), eip =3D 0x805a9df, esp =3D 0xb=
fbfd88c, ebp =3D 0xbfbfd960 ---
KDB: enter: panic
[ thread pid 1 tid 100002 ]
Stopped at      kdb_enter+0x3d: movl    $0,kdb_why
db> show locks
exclusive sleep mutex Giant (Giant) r =3D 0 (0xc1724910) locked @ /usr/src/=
sys/vm/swap_pager.c:2365
db>=20


When I issued "reset", the machine came back up normally (in slice
1 -- stable/9).  I then rebooted to slice 4 (head), and issued the
same commands I usually do to set the default boot slice back to 1, then
"shutdown -p now" -- and re-created the panic.

I can leave the machine up for a while if anyone has suggestions for me
to poke around.  I have a local private mirror of the FreeBSD SVN repos
and a spare bootable slice; I'm williing to try patches.  The machine
isn't especially fast, but it's generally OK.

If it would be worthwhile, I could reboot my laptop to slice 4 (head) &
attempt the same reset-to-slice-1-default & power-off.

This definitely did not happen @r260875, and it appears to be quite
repeatable @r260904.

Peace,
david
--=20
David H. Wolfskill				david@catwhisker.org
Taliban: Evil cowards with guns afraid of truth from a 14-year old girl.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.

--IUSVF+LtaR4kWxuH
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (FreeBSD)
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=uO0i
-----END PGP SIGNATURE-----

--IUSVF+LtaR4kWxuH--



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20140120153615.GS1789>