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Date: Thu, 5 Sep 2002 01:45:02 -0700
From: William Lee Irwin III <wli@holomorphy.com>
To: Andrew Morton <akpm@zip.com.au>, linux-kernel@vger.kernel.org
Subject: Re: [BUG] __write_lock_failed() oops
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On Thu, Sep 05, 2002 at 01:42:52AM -0700, Andrew Morton wrote:
>> That's all the assembly hacks in the rwlock code not having proper
>> stack frames.  You may have to ksymoops it.
>> At a guess: use-after-free bug against an address_space.  You may
>> be able to catch it with slab poisoning.

On Thu, Sep 05, 2002 at 01:32:40AM -0700, William Lee Irwin III wrote:
> (gdb) p/x $eax
> $25 = 0xc0331ca0
> (gdb) p &tasklist_lock
> $27 = (rwlock_t *) 0xc0331ca0

The NMI oopser is going here as well (nmi_watchdog=2 for extra safety)
so I suspect the tasklist_lock semantics are behaving badly. But it's
not easily reproducible enough to test a quick attempt at a fix if it
can't be recognized a priori.

This is literally so difficult to reproduce it hasn't been seen in 2
releases. kgdb is still going and dhowells is helping me fish stuff
off the stack.


Cheers,
Bill
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