Kernel panic within dummynet-code(?)

[Ruslan Ermilov]

On Thu, Feb 23, 2006 at 11:07:06AM +0100, Sebastian Inacker wrote:
> Hello Networkers.
> 
> I got a kernel panic on FreeBSD 6.0-RELEASE, which is probably caused
> by a not initialised pointer "p = (void *) 0x0" within the
> dummynet-code.
> 
> I analysed the crash dump and got
> 
>   (kgdb) f 9
>   #9  0xc06d3670 in dummynet (unused=0x0) at ../../../netinet/ip_dummynet.c:785
> 
>   (kgdb) i loc
>   p = (void *) 0x0
>   h = (struct dn_heap *) 0x4
>   heaps = {0xc093cf40, 0xc093cf60, 0xc093cf50}
>   i = 22
>   pe = (struct dn_pipe *) 0x4
> 
> (see backtrack[1] of the crash dump).
> 
> Some frames before I do have problems with subr_turnstile.c and
> kern_mutex.c, which could be caused by a problem in dummynet - but I'm
> not sure.
> 
> The machine does use dummynet (with DUMMYNET and HZ=1000) for
> bandwidth management, but the problem - if it is within dummynet -
> have to be a special case, because it crashes not as regulary as it
> would do in other cases.
> 
> I'd be glad, if someone can help me.
> I would be glad also if I could help to fix a maybe existing bug.
> 
There were several dummynet(4) fixes in RELENG_6, try with them
first.  One that can be responsible for what you're seeing was
insufficient locking.


Cheers,
-- 
Ruslan Ermilov
ru at FreeBSD.org
FreeBSD committer
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