From: Jarek Poplawski <jarkao2@o2.pl>
To: netdev@vger.kernel.org
Subject: Re: [PATCH] locking bug in fib_semantics.c
Date: Mon, 21 Aug 2006 10:16:43 +0200 [thread overview]
Message-ID: <20060821081642.GA2637@ff.dom.local> (raw)
In-Reply-To: <20060817093615.GA25553@ms2.inr.ac.ru>
On 17-08-2006 11:36, Alexey Kuznetsov wrote:
> Hello!
>
> [IPV4]: severe locking bug in fib_semantics.c
>
> The patch is for net-2.6.19, but the bug is present in all the kernels
> since yore.
>
> Found in 2.4 by Yixin Pan <yxpan@hotmail.com>. Why do we need lockdep,
> when sharp-sighted eyes are available? :-)
>
>> When I read fib_semantics.c of Linux-2.4.32, write_lock(&fib_info_lock) =
>> is used in fib_release_info() instead of write_lock_bh(&fib_info_lock). =
>> Is the following case possible: a BH interrupts fib_release_info() while =
>> holding the write lock, and calls ip_check_fib_default() which calls =
>> read_lock(&fib_info_lock), and spin forever.
But I hope the real reason for this patch isn't exactly like that.
Could fib_release_info() be interrupted by BH really?
Jarek P.
next prev parent reply other threads:[~2006-08-21 8:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-17 9:36 [PATCH] locking bug in fib_semantics.c Alexey Kuznetsov
2006-08-18 1:29 ` David Miller
2006-08-21 8:16 ` Jarek Poplawski [this message]
2006-08-21 8:17 ` David Miller
2006-08-21 11:02 ` Jarek Poplawski
2006-08-22 10:35 ` Jarek Poplawski
2006-08-23 6:34 ` Jarek Poplawski
2006-08-23 18:31 ` Stephen Hemminger
2006-08-24 11:04 ` Jarek Poplawski
2006-08-24 14:18 ` Stephen Hemminger
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