From: Lars Ellenberg <lars.ellenberg@linbit.com>
To: drbd-dev@lists.linbit.com
Subject: Re: [Drbd-dev] integer signedness mixup problem in drbd_main.c
Date: Tue, 22 Mar 2016 11:25:17 +0100 [thread overview]
Message-ID: <20160322102517.GG4437@soda.linbit> (raw)
In-Reply-To: <20160321231817.GI30157@schiffbauer.net>
On Tue, Mar 22, 2016 at 12:18:17AM +0100, Marc Schiffbauer wrote:
> hi all,
>
> using a kernel hardened with grsecurity/PaX we discovered a problem
> where PaX detects a size overflow after a quite large uptime:
>
> PAX: size overflow detected in function drbd_send_dblock
> drivers/block/drbd/drbd_main.c:1625 cicus.964_133 max, count: 1
>
> this was in kernel 3.14.19, but 4.4.5 still seems to have that problem.
> The line triggering this is:
>
> p->seq_num = cpu_to_be32(atomic_inc_return_unchecked(&mdev->packet_seq));
Boring.
seq_num should give it away: it is a sequence number.
it wraps. that's what sequence numbers do, eventually.
haven't we been here before?
--
: Lars Ellenberg
: LINBIT | Keeping the Digital World Running
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next prev parent reply other threads:[~2016-03-22 10:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-21 23:18 [Drbd-dev] integer signedness mixup problem in drbd_main.c Marc Schiffbauer
2016-03-22 10:25 ` Lars Ellenberg [this message]
2016-03-22 12:32 ` Marc Schiffbauer
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