Date: Tue, 09 Dec 2003 13:44:22 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Robin Breathe <robin@isometry.net> Cc: current@freebsd.org Subject: Re: Fatal trap 12: page fault while in kernel mode (subr_turnstile.c) w/ trace Message-ID: <XFMail.20031209134422.jhb@FreeBSD.org> In-Reply-To: <3FD508A7.3010901@isometry.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On 08-Dec-2003 Robin Breathe wrote:
> John Baldwin wrote:
>> On 08-Dec-2003 Robin Breathe wrote:
>>>I've been experiencing the following repeatable panic on recent
>>>-CURRENT. This one is against RELENG_5_2, as of around 18:00 UT today.
>>>Until now I've not been able to get a dump, but thankfully one's finally
>>>come :)
>>
>> If you can reproduce the panic with INVARIANTS, it would be very useful
>> to know which, if any, assertions it trips.
>
> Here's the output from DDB with INVARIANTS enabled, does it contain what
> you need?
>
> I think I spotted the error in my ways on failing to use previous forced
> dumps (it won't dump itself without my doing a 'call doadump' manually),
> so I have both DDB and GDB output.
Oof, you seem to have possibly hit a corrupted thread object.
> (kgdb) l *0xc0537aa6
> 0xc0537aa6 is in turnstile_wait (/usr/src/sys/kern/subr_turnstile.c:439).
> 434 td = curthread;
> 435 tc = TC_LOOKUP(lock);
> 436 mtx_assert(&tc->tc_lock, MA_OWNED);
> 437 MPASS(td->td_turnstile != NULL);
> 438 MPASS(owner != NULL);
> 439 MPASS(owner->td_proc->p_magic == P_MAGIC);
> 440
> 441 /* If the passed in turnstile is NULL, use this thread's
> turnstile. */
> 442 if (ts == NULL) {
> 443 ts = td->td_turnstile;
> (kgdb)
owner is not NULL, but it blew up trying to read owner->td_proc.
Hmm, actually then, I think the owner pointer is bad. There was
a while after one of the KSE commits when people would get panics
with a thread whose td_proc was NULL, but I don't know if that bug
was ever figured out or fixed. For owner to be wrong though,
mtx_lock in the relevant mutex must have been corrupted somehow.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?XFMail.20031209134422.jhb>