From: Russell King <rmk@arm.linux.org.uk>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arch@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [BUG] Fault handlers can deadlock
Date: Mon, 11 Jun 2007 18:38:15 +0100 [thread overview]
Message-ID: <20070611173815.GC16265@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20070611103142.a9e55928.akpm@linux-foundation.org>
On Mon, Jun 11, 2007 at 10:31:42AM -0700, Andrew Morton wrote:
> The code is there to improve debuggability and for no other reason. It is
> to fix the situation where the kernel references an invalida address while
> holding down_write(mmap_sem). We used to take the fault and then deadlock
> on do_page_fault()'s down_read(). Now, we do the trylock and if that fails
> we chech that a) it was running kernel code and b) the kernel didn't expect
> a fault to occur at that EIP. If both of those are true, go off and report
> the oops rather than deadlocking.
>
> And I don't think I spot anything in either the ARM or i386 comments which
> contradicts that?
No, I think ARM is right and there isn't a problem (apart from
ambiguous comments), provided people use a recent enough kernel.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
next prev parent reply other threads:[~2007-06-11 17:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-11 16:00 [BUG] Fault handlers can deadlock Russell King
2007-06-11 16:41 ` Andrew Morton
2007-06-11 16:53 ` Russell King
2007-06-11 17:31 ` Andrew Morton
2007-06-11 17:38 ` Russell King [this message]
2007-06-11 17:51 ` Linus Torvalds
2007-06-11 17:39 ` Linus Torvalds
2007-06-11 18:08 ` Russell King
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