From: Andrew Morton <akpm@zip.com.au>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: linux-kernel@vger.kernel.org, Marcelo Tosatti <marcelo@conectiva.com.br>
Subject: Re: [patch] block/IDE/interrupt lockup
Date: Sat, 30 Mar 2002 10:28:00 -0800 [thread overview]
Message-ID: <3CA603B0.8B73FD4C@zip.com.au> (raw)
In-Reply-To: <001d01c1d7ce$34f830c0$010411ac@local>
Manfred Spraul wrote:
>
> > - spin_unlock_irq(&io_request_lock);
> > + spin_unlock_irqrestore(&io_request_lock, flags);
> > rq = kmem_cache_alloc(request_cachep, SLAB_KERNEL);
>
> Great patch.
> kmem_cache_alloc with SLAB_KERNEL can sleep, i.e. you've just converted
> an obvious bug into a rare, difficult to find bug. What about trying to
> fix it?
Gimme a break, Manfred. The patch fixes the new bug. Which was
hardly obvious. The longstanding (as in years-old) bug was
pointed out to the maintainer.
It may not even be a bug. Certainly I don't think it's
worth my time to fiddle with it. But you're at liberty to.
> I agree that this won't happen during boot, but what about a hotplug PCI
> ide controller?
The kernel calls request_irq() inside cli() in lots of places.
That's the same bug: "if you called cli(), how come you're
allowing kmalloc to clear it?".
In 2.4, this is a design wart. In 2.5, it will go BUG() if
the page allocator performs I/O.
-
next prev parent reply other threads:[~2002-03-30 18:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-30 9:35 [patch] block/IDE/interrupt lockup Manfred Spraul
2002-03-30 18:28 ` Andrew Morton [this message]
2002-03-30 18:52 ` Alan Cox
2002-03-30 19:06 ` Andrew Morton
2002-03-30 23:23 ` Keith Owens
-- strict thread matches above, loose matches on Subject: below --
2002-04-01 9:23 Manfred Spraul
2002-03-30 5:45 Andrew Morton
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