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Subject: Re: Locking question, is this cool?
To: george@mvista.com (George Anzinger)
Date: Tue, 31 Oct 2000 19:01:30 +0000 (GMT)
Cc: linux-kernel@vger.kernel.org (linux-kernel@vger.redhat.com)
In-Reply-To: <39FF14C9.33AE7325@mvista.com> from "George Anzinger" at Oct 31, 2000 10:51:53 AM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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> At line 1073 of ../drivers/char/i2lib.c (2.4.0-test9) we find:
> 
> WRITE_LOCK_IRQSAVE(...
> 
> this is followed by:
> 
> COPY_FROM_USER(...
> 
> It seems to me that this could result in a page fault with interrupts
> off.  Is this ok?

It wont do what you want - it'll re-enable irqs and may then deadlock. It might
need to copy the buffer to a temporary space then take the lock >
-
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