9.0-RC1 panic in tcp_input: negative winow.

[Коньков Евгений]

Здравствуйте, John.

Вы писали 20 декабря 2011 г., 16:52:44:

JB> On Saturday, December 17, 2011 6:21:27 pm Pawel Jakub Dawidek wrote:
>> On Mon, Dec 12, 2011 at 11:00:23AM -0500, John Baldwin wrote:
>> > An update.  I've sent Pawel a testing patch to see if my hypothesis is correct
>> > (www.freebsd.org/~jhb/patches/tcp_negwin_test.patch).  If it is then I intend
>> > to commit www.freebsd.org/~jhb/patches/tcp_negwin2.patch as the fix.
>> 
>> Unfortunately it paniced today. Take a look at:
>> 
>>       http://people.freebsd.org/~pjd/misc/tcp_panic.jpg

JB> Ok, the one use case I was worried about is happening regularly before your
JB> panic, so that is good.  Can you use gdb to figure out which call to
JB> tcp_output() is actually panic'ing?  I wonder if it is this case:

JB>         /*
JB>          * Return any desired output.
JB>          */
JB>         if (needoutput || (tp->t_flags & TF_ACKNOW)) {
JB>                 (void) tcp_output(tp);
JB>                 /* XXX: Debug */
JB>                 KASSERT(SEQ_GEQ(tp->rcv_adv, tp->rcv_nxt),
JB>                     ("tcp_input: negative window after ACK"));

JB> And if 'needoutput' is true, but TF_ACKNOW is not set, and tcp_output() decides
JB> to not do anything.  I've updated tcp_negwin_test.patch to not panic if that call
JB> to tcp_output() doesn't actually send a packet.  Please re-test.


# uname -a
FreeBSD meta-up 9.0-PRERELEASE FreeBSD 9.0-PRERELEASE #4: Sat Dec 24 13:59:20 EET 2011     @:/usr/obj/usr/src/sys/KES_KERN_v10  i386

rebooting once per day. Now I compile kernel with debug options.
Can you advice me which and where I find debug info when it will
reboting next time? so I can help to debug problem

-- 
С уважением,
 Коньков                          mailto:kes-kes at yandex.ru