linux-kernel - [v2 PATCH 0/2] crypto: Fix race condition in *_check

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Message-ID: <20160115135900.GA31813@gondor.apana.org.au>
Date:	Fri, 15 Jan 2016 21:59:00 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Dmitry Vyukov <dvyukov@...gle.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	linux-crypto@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	syzkaller <syzkaller@...glegroups.com>,
	Kostya Serebryany <kcc@...gle.com>,
	Alexander Potapenko <glider@...gle.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Sasha Levin <sasha.levin@...cle.com>
Subject: [v2 PATCH 0/2] crypto: Fix race condition in *_check_key

On Fri, Jan 15, 2016 at 10:06:11AM +0100, Dmitry Vyukov wrote:
> 
> With these patches I see lots of:
> 
> [ INFO: possible recursive locking detected ]
> 4.4.0+ #250 Not tainted
> ---------------------------------------------
> syz-executor/16742 is trying to acquire lock:
>  (sk_lock-AF_ALG){+.+.+.}, at: [<     inline     >] lock_sock
> include/net/sock.h:1480
>  (sk_lock-AF_ALG){+.+.+.}, at: [<ffffffff828661d2>]
> hash_check_key.isra.3+0xd2/0x210 crypto/algif_hash.c:261
> 
> but task is already holding lock:
>  (sk_lock-AF_ALG){+.+.+.}, at: [<     inline     >] lock_sock
> include/net/sock.h:1480
>  (sk_lock-AF_ALG){+.+.+.}, at: [<ffffffff82866126>]
> hash_check_key.isra.3+0x26/0x210 crypto/algif_hash.c:252
> 
> other info that might help us debug this:
>  Possible unsafe locking scenario:
> 
>        CPU0
>        ----
>   lock(sk_lock-AF_ALG);
>   lock(sk_lock-AF_ALG);
> 
>  *** DEADLOCK ***
> 
>  May be due to missing lock nesting notation

Indeed.  Here is an updated version.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt