Re: panic: sleeping thread owns a non-sleepable lock

On 8/16/07, Max Laier <max_at_love2party.net> wrote:
> On Wednesday 15 August 2007, Rong-en Fan wrote:
> > On 8/12/07, Max Laier <max_at_love2party.net> wrote:
> > > On Saturday 11 August 2007, Kris Kennaway wrote:
> > > > On Sun, Aug 12, 2007 at 02:22:35AM +0800, Rong-en Fan wrote:
> > > > > I'm running 7.0-CURRENT as of  yesterday, and it's very easy
> > > > > to make it panic:
> > > > >
> > > > > Sleeping thread (tid 100065, pid 1066) owns a non-sleepable lock
> > > > > sched_switch(c50a1600,0,1,1c7a7e4,4217e5,...) at
> > > > > sched_switch+0x190 mi_switch(1,0) at mi_switch+0x13f
> > > > > sleepq_switch(c50a1600,0,c078a4e2,21b,c07e3820,...) at
> > > > > sleepq_switch+0x87 sleepq_wait(c07e3820,0,c0770b7e,3,0,...) at
> > > > > sleepq_wait+0x36 _sx_xlock_hard(c07e3820,c50a1600,0,0,0,...) at
> > > > > _sx_xlock_hard+0x21d
> > > > > fr_checknatout(f9c7a8d0,f9c7a8cc,64,c57ad900,c4de7400,...) at
> > > > > fr_checknatout+0x29d
> > > > > fr_check(c8cc4644,14,c4de7400,1,f9c7a9b4,...) at fr_check+0x9b1
> > > > > fr_check_wrapper(0,f9c7a9b4,c4de7400,2,c54dab28,...) at
> > > > > fr_check_wrapper+0x3f
> > > > > pfil_run_hooks(c08057c0,f9c7aa4c,c4de7400,2,c54dab28,...) at
> > > > > pfil_run_hooks+0x74 ip_output(c8cc4600,0,f9c7aa10,0,0,...) at
> > > > > ip_output+0x913
> > > > > tcp_output(cae322d0,cb277200,0,0,0,...) at tcp_output+0x1106
> > > > > tcp_usr_send(c51e7318,0,cb277200,0,0,...) at tcp_usr_send+0x240
> > > > > kern_sendfile(c50a1600,f9c7acfc,0,0,0,...) at
> > > > > kern_sendfile+0x1037
> > > > > sendfile(c50a1600,f9c7acfc,20,16,f9c7ad2c,...) at sendfile+0xa8
> > > > > syscall(f9c7ad38) at syscall+0x315
> > > > > Xint0x80_syscall() at Xint0x80_syscall+0x20
> > > > > --- syscall (393, FreeBSD ELF32, sendfile), eip = 0x28290bff, esp
> > > > > = 0xbfbfc6ac, ebp = 0xbfbfe718 ---
> > > >
> > > > What is the lock it holds, and where is it acquired?
> > >
> > > My bet is on the pfil rwlock - accquired in pfil_run_hooks and
> > > tcbinfo / inp mtxs from tcp_output.  Nothing in the transmission path
> > > must use sx locks.  I keep on telling that.
> >
> > I compiled kernel with WITNESS and INVARIANTS as in GENERIC.
> > After boot, without doing anything (I even set ipnat_enable="NO", i.e.
> > only ipfw is running, but ipf/ipnat is compiled in). I got panic.
> > I don't have serial console attached, but the console screen is at
> >
> > http://www.rafan.org/tmp/pfil_panic.jpg
> >
> > You can find 'show locks', 'show allpcpu', and 'show lock' for each
> > lock. Also two trace for thread that are found in 'show allpcpu'.
> >
> > If necessary, I can setup serial console, but it will take few days.
>
> The problem is understood and has been reported to the ipfilter
> maintainer.  One sollution might be to use rwlocks instead, but if there
> is a path that sleeps with the lock held another sollution might be
> required.  Most likely the ioctl path (on copyin/copyout) exercises that
> problem.

I see. So, only ipfilter has this problem, but not pf and ipfw, right?
Thanks.

Regards,
Rong-En Fan

>
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