Messages in this thread | | | Date | Sat, 30 Mar 2002 10:28:00 -0800 | From | Andrew Morton <> | Subject | Re: [patch] block/IDE/interrupt lockup |
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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.
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