Re: [PATCH] qdisc oops fix

From: Catalin BOIE (util@deuroconsult.ro)
Date: Thu Apr 17 2003 - 01:06:39 EST


> Catalin, Can you what kernel that is?

2.4.20pre10 works ok but 2.4.20 crash.
With traffic -> no crash with 2.4.20. Without traffic, on other machine,
no crash.

> > It's triggered, because someone does something like
> > spin_lock_bh(&my_lock);
> > p = kmalloc(,GFP_KERNEL);
> >
> > I don't like the proposed fix: usually code that calls
> > kmalloc(,GFP_KERNEL) assumes that it runs at process space, e.g. uses
> > semaphores, or non-bh spinlocks, etc.
> > slab just happens to contain a test that complains about illegal calls.
>
> ok. Nice.
>
> >
> > >>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>
> > >>
> > >>
> > >>
> > >>
> > I don't understand the backtrace. Were any modules loaded? Perhaps
> > 0xd081ecc7 is a module.
> >
>
> Probably a module. Again Catalin, run no modules.
It's a production machine. I cannot test this. We plan to replace the
machine, so I can test then.

> > I'd add a
> > if(in_interrupt()) show_stack(NULL);
> > into qdisc_create_dflt(), and try to reproduce the bug without modules.
> >
>
> Catalin - again instead of your fix can you please add this call?
See above. I cannot test now. I'm very sorry!

> cheers,
> jamal
>

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