From owner-freebsd-current@FreeBSD.ORG Sun Dec 21 13:57:11 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E02414C1 for ; Sun, 21 Dec 2014 13:57:10 +0000 (UTC) Received: from smtprelay02.ispgateway.de (smtprelay02.ispgateway.de [80.67.29.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 2D8902B77 for ; Sun, 21 Dec 2014 13:57:09 +0000 (UTC) Received: from [87.79.249.86] (helo=fabiankeil.de) by smtprelay02.ispgateway.de with esmtpsa (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.84) (envelope-from ) id 1Y2h02-0005n1-3B for freebsd-current@freebsd.org; Sun, 21 Dec 2014 14:56:46 +0100 Date: Sun, 21 Dec 2014 14:54:31 +0100 From: Fabian Keil Cc: FreeBSD Current Subject: Re: Panic after USB deadlock followed by kldunload umass.ko Message-ID: <0f51077e.10c32ab3@fabiankeil.de> In-Reply-To: <7af2d4d6.5c73ae4f@fabiankeil.de> References: <03fafb9a.529c7f26@fabiankeil.de> <5449119B.8090401@selasky.org> <7af2d4d6.5c73ae4f@fabiankeil.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/UT8zPZkR/Oor7heql_vRKv4"; protocol="application/pgp-signature" X-Df-Sender: Nzc1MDY3 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Dec 2014 13:57:11 -0000 --Sig_/UT8zPZkR/Oor7heql_vRKv4 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Fabian Keil wrote: > Hans Petter Selasky wrote: >=20 > > On 10/23/14 16:28, Fabian Keil wrote: >=20 > > > kldunload umass.ko lead to a panic, dumping didn't work. > > > > > > Screenshots are available at: > > > http://www.fabiankeil.de/bilder/freebsd/kernel-panic-r273434-usb/ > > > > > > I've seen locked-up usbconfig processes in the past, > > > usually after executing a shell function that does: > > > > > > | usbconfig_output=3D"$(sudo usbconfig -d ${device} add_quirk UQ_MSC_= NO_INQUIRY)" > > > | [... error handling snipped ] > > > | usbconfig_output=3D"$(sudo usbconfig -d ${device} reset)" > > > > > > Sometimes the second command seems to mess up the USB system. >=20 > > USB detach is synchronous. If for example umass fails to detach, due to= =20 > > reference counts not reaching zero, that might be the root cause. Try t= o=20 > > get a backtrace from the "usb_process()" processes using kgdb, and=20 > > you'll see right away what is going on. >=20 > Thanks for the quick response. So far I haven't been able to intentionally > reproduce the issue, but I'll try the above the next time I unintentional= ly > run into this again. A couple of days ago usbconfig got stuck again: fk@r500 ~ $sudo procstat -kk $(pgrep usbconfig) PID TID COMM TDNAME KSTACK = =20 2444 100971 usbconfig - mi_switch+0xe1 sleepq_wait+0= x3a _sx_xlock_hard+0x522 _sx_xlock+0x5d usbd_enum_lock+0x3a usb_ref_device+= 0x157 usb_open+0xbf devfs_open+0x122 VOP_OPEN_APV+0xa1 vn_open_vnode+0x234 = vn_open_cred+0x310 kern_openat+0x26f amd64_syscall+0x3fd Xfast_syscall+0xfb= =20 2425 100970 usbconfig - mi_switch+0xe1 sleepq_timedw= ait+0x3a _sleep+0x294 pause_sbt+0xd0 usb_pause_mtx+0x85 usb_ioctl+0x3e7 dev= fs_ioctl_f+0x13b kern_ioctl+0x3ce sys_ioctl+0x140 amd64_syscall+0x3fd Xfast= _syscall+0xfb=20 The USB-related threads: (kgdb) thread 520 [Switching to thread 520 (Thread 100970)]#0 sched_switch (td=3D0xfffff8001= d2044a0, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff8001d2044a0, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff80601a7a in sleepq_timedwait (wchan=3D0x0, pri=3D0) at /usr/s= rc/sys/kern/subr_sleepqueue.c:666 #3 0xffffffff805bb984 in _sleep (ident=3D, lock=3D, priority=3D, wmesg=3D, sbt=3D, pr=3D,=20 flags=3D) at /usr/src/sys/kern/kern_synch.c:250 #4 0xffffffff805bbe10 in pause_sbt (wmesg=3D, sbt=3D<= value optimized out>, pr=3D0, flags=3D) at /usr/src/sy= s/kern/kern_synch.c:379 #5 0xffffffff81e2f175 in usb_pause_mtx (mtx=3D, timo= =3D) at /usr/src/sys/modules/usb/usb/../../../dev/usb/= usb_util.c:143 #6 0xffffffff81e16ed7 in usb_ioctl (dev=3D, cmd=3D, addr=3D, fflag=3D0, td=3D) at /usr/src/sys/modules/usb/usb/../../../dev/usb/usb_dev.c:1128 #7 0xffffffff8047cffb in devfs_ioctl_f (fp=3D0xfffff8001d3d1b40, com=3D214= 7767558, data=3D0xfffffe009453aa20, cred=3D, td=3D0xff= fff8001d2044a0) at /usr/src/sys/fs/devfs/devfs_vnops.c:775 #8 0xffffffff8061041e in kern_ioctl (td=3D0xfffff8001d2044a0, fd=3D, com=3D0) at file.h:318 #9 0xffffffff8060ffa0 in sys_ioctl (td=3D0xfffff8001d2044a0, uap=3D0xfffff= e009453ab80) at /usr/src/sys/kern/sys_generic.c:718 #10 0xffffffff80877d5d in amd64_syscall (td=3D0xfffff8001d2044a0, traced=3D= 0) at subr_syscall.c:133 #11 0xffffffff8085ac9b in Xfast_syscall () at /usr/src/sys/amd64/amd64/exce= ption.S:390 #12 0x0000000800b7caea in ?? () Previous frame inner to this frame (corrupt stack?) (kgdb) thread 522 [Switching to thread 522 (Thread 100971)]#0 sched_switch (td=3D0xfffff8001= d3a5940, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff8001d3a5940, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff805bae82 in _sx_xlock_hard (sx=3D0xfffff80015e82050, tid=3D18= 446735278106892608, opts=3D, file=3D0x0, line=3D0) at = /usr/src/sys/kern/kern_sx.c:688 #4 0xffffffff805ba6ad in _sx_xlock (sx=3D0x0, opts=3D0, file=3D, line=3D0) at sx.h:154 #5 0xffffffff81e19baa in usbd_enum_lock (udev=3D0xfffff80015e82000) at /us= r/src/sys/modules/usb/usb/../../../dev/usb/usb_device.c:2755 #6 0xffffffff81e18967 in usb_ref_device (cpd=3D0xfffff80015b518c0, crd=3D0= xfffffe009453f630, need_uref=3D) at /usr/src/sys/modul= es/usb/usb/../../../dev/usb/usb_dev.c:231 #7 0xffffffff81e15caf in usb_open (dev=3D, fflags=3D3= , devtype=3D, td=3D0x0) at /usr/src/sys/modules/usb/us= b/../../../dev/usb/usb_dev.c:887 #8 0xffffffff8047ae52 in devfs_open (ap=3D) at /usr/s= rc/sys/fs/devfs/devfs_vnops.c:1108 #9 0xffffffff8091e3d1 in VOP_OPEN_APV (vop=3D, a=3D) at vnode_if.c:467 #10 0xffffffff8067d544 in vn_open_vnode (vp=3D0xfffff8004f4283b0, fmode=3D3= , cred=3D0xfffff80028c83500, td=3D0xfffff8001d3a5940, fp=3D0xfffff800283b6b= e0) at vnode_if.h:196 #11 0xffffffff8067d090 in vn_open_cred (ndp=3D0xfffffe009453f9b0, flagp=3D0= xfffffe009453fa8c, cmode=3D, vn_open_flags=3D, cred=3D0x0, fp=3D0xfffff800283b6be0) at /usr/src/sys/kern/vfs_vnops.c:258 #12 0xffffffff8067674f in kern_openat (td=3D0xfffff8001d3a5940, fd=3D-100, = path=3D0x7fffffffe650
, pathseg=3DUIO= _USERSPACE, flags=3D3, mode=3D) at /usr/src/sys/kern/vfs_syscalls.c:1081 #13 0xffffffff80877d5d in amd64_syscall (td=3D0xfffff8001d3a5940, traced=3D= 0) at subr_syscall.c:133 #14 0xffffffff8085ac9b in Xfast_syscall () at /usr/src/sys/amd64/amd64/exce= ption.S:390 #15 0x0000000800b748aa in ?? () Previous frame inner to this frame (corrupt stack?) (kgdb) thread 497 [Switching to thread 497 (Thread 100728)]#0 sched_switch (td=3D0xfffff8001= 5d51940, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d51940, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe0004590d10, lock=3D0xffff= fe0004591090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe0004590d00) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe0004590d00, frame=3D0xfffffe00942e0c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 496 [Switching to thread 496 (Thread 100731)]#0 sched_switch (td=3D0xfffff8001= 5d50940, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d50940, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe0004590d68, lock=3D0xffff= fe0004591090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe0004590d58) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe0004590d58, frame=3D0xfffffe00942efc00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 495 [Switching to thread 495 (Thread 100732)]#0 sched_switch (td=3D0xfffff8001= 5d504a0, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d504a0, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe0004590dc0, lock=3D0xffff= fe0004591090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe0004590db0) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe0004590db0, frame=3D0xfffffe00942f4c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 495 [Switching to thread 495 (Thread 100732)]#0 sched_switch (td=3D0xfffff8001= 5d504a0, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d504a0, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe0004590dc0, lock=3D0xffff= fe0004591090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe0004590db0) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe0004590db0, frame=3D0xfffffe00942f4c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 494 [Switching to thread 494 (Thread 100733)]#0 sched_switch (td=3D0xfffff8001= 5d50000, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d50000, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe0004590e18, lock=3D0xffff= fe0004591090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe0004590e08) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe0004590e08, frame=3D0xfffffe00942f9c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 493 [Switching to thread 493 (Thread 100735)]#0 sched_switch (td=3D0xfffff8001= 5d7f4a0, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d7f4a0, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe00064a7d10, lock=3D0xffff= fe00064a8090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe00064a7d00) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe00064a7d00, frame=3D0xfffffe0094303c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 492 [Switching to thread 492 (Thread 100736)]#0 sched_switch (td=3D0xfffff8001= 5d7f000, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015d7f000, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe00064a7d68, lock=3D0xffff= fe00064a8090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe00064a7d58) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe00064a7d58, frame=3D0xfffffe0094308c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () (kgdb) thread 491 [Switching to thread 491 (Thread 100737)]#0 sched_switch (td=3D0xfffff8001= 5ea0940, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015ea0940, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff805bb99d in _sleep (ident=3D, lock=3D, priority=3D, wmesg=3D, sbt=3D, pr=3D,=20 flags=3D) at /usr/src/sys/kern/kern_synch.c:254 #4 0xffffffff802a2548 in cam_sim_free (sim=3D0xfffff8004f9fa800, free_devq= =3D1) at /usr/src/sys/cam/cam_sim.c:109 #5 0xffffffff81e4e78f in umass_detach (dev=3D) at /us= r/src/sys/modules/usb/umass/../../../dev/usb/storage/umass.c:2136 #6 0xffffffff805e8ce2 in device_detach (dev=3D0xfffff80028c69000) at devic= e_if.h:214 #7 0xffffffff81e1aad1 in usb_detach_device (udev=3D0xfffff8004f5bd000, ifa= ce_index=3D, flag=3D0 '\0') at /usr/src/sys/modules/us= b/usb/../../../dev/usb/usb_device.c:1145 #8 0xffffffff81e19c76 in usb_unconfigure (udev=3D0xfffff8004f5bd000, flag= =3D0 '\0') at /usr/src/sys/modules/usb/usb/../../../dev/usb/usb_device.c:534 #9 0xffffffff81e196d0 in usbd_set_config_index (udev=3D0xfffff8004f5bd000,= index=3D255 '=C3=BF') at /usr/src/sys/modules/usb/usb/../../../dev/usb/usb= _device.c:597 #10 0xffffffff81e22d77 in uhub_explore_handle_re_enumerate (child=3D0xfffff= 8004f5bd000) at /usr/src/sys/modules/usb/usb/../../../dev/usb/usb_hub.c:456 #11 0xffffffff81e25eb5 in uhub_explore (udev=3D0xfffff80015e82000) at /usr/= src/sys/modules/usb/usb/../../../dev/usb/usb_hub.c:551 #12 0xffffffff81e12f75 in usb_bus_explore (pm=3D) at /= usr/src/sys/modules/usb/usb/../../../dev/usb/controller/usb_controller.c:404 #13 0xffffffff81e2857f in usb_process (arg=3D0xfffffe00064a7db0) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:176 #14 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe00064a7db0, frame=3D0xfffffe009430dc00) at /usr/src/sys= /kern/kern_fork.c:978 #15 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #16 0x0000000000000000 in ?? () (kgdb) thread 490 [Switching to thread 490 (Thread 100738)]#0 sched_switch (td=3D0xfffff8001= 5ea04a0, newtd=3D, flags=3D) at /= usr/src/sys/kern/sched_ule.c:1940 1940 cpuid =3D PCPU_GET(cpuid); (kgdb) where #0 sched_switch (td=3D0xfffff80015ea04a0, newtd=3D, f= lags=3D) at /usr/src/sys/kern/sched_ule.c:1940 #1 0xffffffff805bbf91 in mi_switch (flags=3D260, newtd=3D0x0) at /usr/src/= sys/kern/kern_synch.c:492 #2 0xffffffff8060126a in sleepq_wait (wchan=3D0x0, pri=3D0) at /usr/src/sy= s/kern/subr_sleepqueue.c:631 #3 0xffffffff80553340 in _cv_wait (cvp=3D0xfffffe00064a7e18, lock=3D0xffff= fe00064a8090) at /usr/src/sys/kern/kern_condvar.c:139 #4 0xffffffff81e28544 in usb_process (arg=3D0xfffffe00064a7e08) at /usr/sr= c/sys/modules/usb/usb/../../../dev/usb/usb_process.c:193 #5 0xffffffff80577afa in fork_exit (callout=3D0xffffffff81e28470 , arg=3D0xfffffe00064a7e08, frame=3D0xfffffe0094312c00) at /usr/src/sys= /kern/kern_fork.c:978 #6 0xffffffff8085aeee in fork_trampoline () at /usr/src/sys/amd64/amd64/ex= ception.S:605 #7 0x0000000000000000 in ?? () So it looks like thread 491 is blocking thread 522 by holding udev->enum_sx? Fabian --Sig_/UT8zPZkR/Oor7heql_vRKv4 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlSW0RQACgkQBYqIVf93VJ2cJwCghFg7LM7J2lqwfR8vT0Ld97Fe uEAAoLTT+TyhWNMdZhFqKdPkL2CeGgmd =4D4/ -----END PGP SIGNATURE----- --Sig_/UT8zPZkR/Oor7heql_vRKv4--