From: Rajesh Venkatasubramanian <vrajesh@umich.edu>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, Linux-MM@kvack.org
Subject: Re: [PATCH] mremap NULL pointer dereference fix
Date: Tue, 17 Feb 2004 08:23:34 -0500 (EST) [thread overview]
Message-ID: <Pine.SOL.4.44.0402170821070.13429-100000@azure.engin.umich.edu> (raw)
In-Reply-To: <Pine.LNX.4.58.0402162203230.2154@home.osdl.org>
> To trigger the bug you have to have _just_ the right memory usage, I
> suspect. You literally have to have the destination page directory
> allocation unmap the _exact_ source page (which has to be clean) for the
> bug to hit.
>
To trigger the bug, I have to run my test program in a "while true;"
loop for an hour or so.
> So I suspect the oops only triggers on the machine that the trigger
> program was written for.
>
> Your version of the patch saves a goto in the source, but results in an
> extra goto in the generated assembly unless the compiler is clever enough
> to notice the double test for NULL.
>
> Never mind, that's a micro-optimization, and your version is cleaner.
> Let's go with it if Rajesh can verify that it fixes the problem for him.
I will test the patch and report.
Thanks,
Rajesh
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next prev parent reply other threads:[~2004-02-17 13:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-17 4:41 Rajesh Venkatasubramanian
2004-02-17 5:31 ` Andrew Morton
2004-02-17 5:38 ` Linus Torvalds
2004-02-17 5:49 ` Linus Torvalds
2004-02-17 6:00 ` Andrew Morton
2004-02-17 6:06 ` Linus Torvalds
2004-02-17 13:23 ` Rajesh Venkatasubramanian [this message]
2004-02-17 21:33 ` Rajesh Venkatasubramanian
2004-02-19 14:29 ` [PATCH] orphaned ptes -- mremap vs. truncate race Rajesh Venkatasubramanian
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