Re: [PATCH] qdisc oops fix

From: Catalin BOIE (util@deuroconsult.ro)
Date: Thu Apr 17 2003 - 00:13:26 EST


Hi!

> This is a different problem from previous one posted.
Same oops in slab.c:1128. Why do you think is different.

> Theres a small window (exposed given that you are provisioning a lot
> of qdiscs and running traffic at the same time) that an incoming packet
> interupt will cause the BUG().
>
> GFP_ATOMIC will fix it, but i wonder if it appropriate.
>
> Alexey or Manfred?
>
> cheers,
> jamal
>
> PS:- 15mbits is not a lot of traffic ;->
Yes, I know. I was comparing 15mbit with almost no traffic on the machine
running same qdiscs/filters/classes... :)

>
> On Wed, 16 Apr 2003, Catalin BOIE wrote:
>
> > > - sch = kmalloc(size, GFP_KERNEL);
> > > + sch = kmalloc(size, GFP_ATOMIC);
> > >
> > > mysteriously fixes the problem? Could the problem be elsewhere?
> > > Can you repost what the issue was? I am not on lk and i just saw the
> > > posting on a web page.
> >
> > With many rules (~5000 classes and ~3500 qdiscs and ~50000 filters)
> > the kernel oopses in slab.c:1128.
> > It happens on high rates (~15mbit).
> > On low rates, doesn't.
> >
> > Seems that an interrupt come and broke the memory allocation.
> >
> >
> > >>EIP; c0127ab4 <kmem_cache_grow+44/1d8> <=====
> >
> > >>EAX; ffffffff <END_OF_CODE+3fd31247/????>
> > >>EBX; c12c52c0 <END_OF_CODE+ff6508/????>
> > >>EDI; c12c52c0 <END_OF_CODE+ff6508/????>
> > >>ESP; ceab1c60 <END_OF_CODE+e7e2ea8/????>
> >
> > Trace; c0127e0f <kmalloc+eb/110>
> > Trace; c01d3cac <qdisc_create_dflt+20/bc>
> > Trace; d081ecc7 <END_OF_CODE+1054ff0f/????>
> > Trace; c01d5265 <tc_ctl_tclass+1cd/214>
> > Trace; d0820600 <END_OF_CODE+10551848/????>
> > Trace; c01d27e4 <rtnetlink_rcv+298/3bc>
> > Trace; c01d0605 <__neigh_event_send+89/1b4>
> > Trace; c01d7cd4 <netlink_data_ready+1c/60>
> > Trace; c01d7730 <netlink_unicast+230/278>
> > Trace; c01d7b73 <netlink_sendmsg+1fb/20c>
> > Trace; c01c79d5 <sock_sendmsg+69/88>
> > Trace; c01c8b48 <sys_sendmsg+18c/1e8>
> > Trace; c0120010 <map_user_kiobuf+8/f8>
> >
> >
>

---
Catalin(ux) BOIE
catab@deuroconsult.ro
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