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List:       linux-kernel
Subject:    Re: Locking question, is this cool?
From:       George Anzinger <george () mvista ! com>
Date:       2000-10-31 19:43:51
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Alan Cox wrote:
> 
> > 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 >
> -
I suspected as much.  I see the same error (bug?) at line 978 of
../drivers/char/riotty.c

Seems like a common problem.

george
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