From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>,
mpm@selenic.com, rjw@sisk.pl, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch] slob: fix memory corruption
Date: Fri, 16 Nov 2007 07:25:12 +1100 [thread overview]
Message-ID: <200711160725.13067.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <20071115124844.GA6606@elte.hu>
On Thursday 15 November 2007 23:48, Ingo Molnar wrote:
> > From: Nick Piggin <npiggin@suse.de>
> >
> > - if (free_slob_pages.next != prev->next)
> > + if (prev != free_slob_pages.prev &&
> > + free_slob_pages.next != prev->next)
> > list_move_tail(&free_slob_pages, prev->next);
>
> btw., exactly how did you find this bug? User-space simulation of SLOB?
Yes. It was very useful in developing the improvements to the freelist
handling. The only reason why I don't release/run the code more often
is that my test harness work is pretty ugly (ie. it isn't just a simple
cp mm/slob.c ../blah/).
After that, just a loop of N iterations, within each iteration, there is
a chance of a single allocation of a random size, a single free of a
random outstanding allocation, a run of allocating MAX allocations, or
a run of freeing all previously allocated memory. It's a bit crude, but
it showed up your list head corruption in a second or two.
next prev parent reply other threads:[~2007-11-15 21:03 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-11 19:58 2.6.24-rc2: Reported regressions from 2.6.23 (updated) Rafael J. Wysocki
2007-11-11 20:09 ` Alan Cox
2007-11-11 20:34 ` Rafael J. Wysocki
2007-11-11 22:22 ` Bartlomiej Zolnierkiewicz
2007-11-11 22:46 ` Alan Cox
2007-11-13 1:11 ` Andrew Morton
2007-11-13 14:09 ` Thomas Lindroth
[not found] ` <3d08dbff0711130534k702f66ebj1f8e91d107eff2a1@mail.gmail.com>
2007-11-13 19:52 ` Andrew Morton
2007-11-11 20:30 ` Ingo Molnar
2007-11-11 20:33 ` Francois Romieu
2007-11-14 11:20 ` [bug] SLOB crash, 2.6.24-rc2 Ingo Molnar
2007-11-14 17:36 ` Matt Mackall
2007-11-14 18:39 ` Matt Mackall
2007-11-14 19:05 ` Ingo Molnar
2007-11-14 19:42 ` Matt Mackall
2007-11-14 22:39 ` David Miller
2007-11-14 22:53 ` Matt Mackall
2007-11-14 23:10 ` David Miller
2007-11-14 23:37 ` Matt Mackall
2007-11-14 23:41 ` David Miller
2007-11-15 0:09 ` Matt Mackall
2007-11-15 10:43 ` Ingo Molnar
2007-11-15 10:51 ` David Miller
2007-11-15 11:03 ` Ingo Molnar
2007-11-15 11:05 ` David Miller
2007-11-15 10:57 ` Nick Piggin
2007-11-15 11:28 ` Ingo Molnar
2007-11-15 11:32 ` [patch] slob: fix memory corruption Ingo Molnar
2007-11-15 12:48 ` Ingo Molnar
2007-11-15 20:25 ` Nick Piggin [this message]
2007-11-15 16:00 ` Matt Mackall
2007-11-15 11:39 ` [bug] SLOB crash, 2.6.24-rc2 Nick Piggin
2007-11-15 12:18 ` Dave Haywood
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