linux-kernel - Re: [PATCH] [RFC] udp: ipv4: fix potential deadlock on sk_dst

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 16 Dec 2013 23:45:20 +0100 (CET)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Eric Dumazet <eric.dumazet@...il.com>
cc:	Eric Dumazet <edumazet@...gle.com>,
	Shawn Bohrer <sbohrer@...advisors.com>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [RFC] udp: ipv4: fix potential deadlock on sk_dst_lock

On Mon, 16 Dec 2013, Eric Dumazet wrote:

> > Commit 975022310 ("udp: ipv4: must add synchronization in 
> > udp_sk_rx_dst_set()) caused sk_dst_lock to be obtained in udp4 receive 
> > path, which is happening in softirq context.
> > 
> > inet_bind() is taking sk_dst_lock (through sk_dst_reset()) without turning 
> > IRQs off, which results in the lockdep splat below.
> > 
> > Fix that by disabling IRQs while taking the lock in sk_dst_reset().
> 
> Thanks but I posted this fix instead :
> 
>  http://patchwork.ozlabs.org/patch/301382/

Right, I missed the incarnation in sk_dst_set(), so my patch is apparently 
incomplete anyway.

But using xchg also fixes the issue.

Thanks,

-- 
Jiri Kosina
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/