linux-kernel - Question on debugging use-after-free memory issues.

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Message-ID: <4E08C80B.9070602@candelatech.com>
Date:	Mon, 27 Jun 2011 11:12:27 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Question on debugging use-after-free memory issues.

I have a case where deleted memory is being passed into an RPC
callback.  I enabled SLUB memory poisoning and verified that the
data pointed to has 0x6b...6b value.

Unfortunately, the rpc code is a giant maze of callbacks and I'm
having a difficult time figuring out where this data could be erroneously
deleted at.

So first question:

Given a pointer to memory, and with SLUB memory debuging on (and/or other
debugging options if applicable), is there a way to get any info about where
the memory was last deleted?

Second:  Any other suggestions for how to go about debugging this?

I hit this problem under load after multiple hours, so just adding printks
in random places may not be feasible...

Thanks,
Ben

-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com

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