Re: [PANIC]: rw_lock panic in in_pcballoc() in r185864

On Wed, 10 Dec 2008, Roman Divacky wrote:

> hm... I wondered how it could work before that.... anyway, I got this crash

Well, nothing says it still works that way, that's just the theory :-).

>> So, given that this code has worked for quite a long time for many people, 
>> this really raises two questions: (1) how reproduceable is this and at what 
>> point does it kick in during the boot/runtime, and (2) when did this start 
>> happening in terms of updating your source?
>
> ad (1): I get this on every boot when dhcp kicks in (it uses udp I believe) 
> ie. 100% reproducible
>
> ad (2): Mon Dec 8 23:02:27 CET 2008 kernel (svn up-dated at most 10 minutes 
> before that) works 100% ok
>
> I have the crash dump and the kernel at hand so I can do basically anything 
> you ask me to do :) anything I can provide?

Well, to be honest, the easiest thing to do may be to play the binary search 
game to narrow down the point where the problem starts a bit more.  There are 
a few kinds of things that might lead to this problem -- perhaps we (I?) 
mucked up initialization of the inpcb with recent changes, or a 
virtualization-related change tripped something up, or a locking/scheduler 
change or such.

The other thing that would be helpful is a dump of *inp so that we can see 
what state inp_lock is in.

Robert N M Watson
Computer Laboratory
University of Cambridge