Date: Thu, 18 Nov 2004 09:21:04 -0500 (EST)
From: linux-os <linux-os@chaos.analogic.com>
Reply-To: linux-os@analogic.com
To: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Signal handler deadlock
Message-ID: <Pine.LNX.4.61.0411180916510.6160@chaos.analogic.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Hello,

If I have a MUTEX in a driver and the driver can
also be called from a signal handler, will the
MUTEX deadlock when the signal handler calls the
driver?

Code --->----> driver-->MUTEX-taken-->***SIGNAL***

Signal handler --->driver--->MUTEX-waiting (will it deadlock?)

I use 'down()' and 'up()' in the driver. With Linux-2.4.22 the
code does not deadlock. With Linux-2.6.9, it does.

Is this the expected behavior? FYI I wrote the driver, not the
dumb code that calls it from a signal handler. I would never
have called anything by printf() from such a handler, so
don't preach to the choir. I just need to know if it should
work, before I tell somebody to rewrite some code.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.9 on an i686 machine (5537.79 BogoMips).
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