netdev - [PATCH] net af_key: Fix RCU splat

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-next>] [day] [month] [year] [list]

Message-Id: <1440085900-8917-1-git-send-email-dsa@cumulusnetworks.com>
Date:	Thu, 20 Aug 2015 08:51:40 -0700
From:	David Ahern <dsa@...ulusnetworks.com>
To:	steffen.klassert@...unet.com, netdev@...r.kernel.org
Cc:	David Ahern <dsa@...ulusnetworks.com>
Subject: [PATCH] net af_key: Fix RCU splat

Hit the following splat testing VRF change for ipsec:

[  113.475692] ===============================
[  113.476194] [ INFO: suspicious RCU usage. ]
[  113.476667] 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED Not tainted
[  113.477545] -------------------------------
[  113.478013] /work/monster-14/dsa/kernel.git/include/linux/rcupdate.h:568 Illegal context switch in RCU read-side critical section!
[  113.479288]
[  113.479288] other info that might help us debug this:
[  113.479288]
[  113.480207]
[  113.480207] rcu_scheduler_active = 1, debug_locks = 1
[  113.480931] 2 locks held by setkey/6829:
[  113.481371]  #0:  (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff814e9887>] pfkey_sendmsg+0xfb/0x213
[  113.482509]  #1:  (rcu_read_lock){......}, at: [<ffffffff814e767f>] rcu_read_lock+0x0/0x6e
[  113.483509]
[  113.483509] stack backtrace:
[  113.484041] CPU: 0 PID: 6829 Comm: setkey Not tainted 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED
[  113.485422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014
[  113.486845]  0000000000000001 ffff88001d4c7a98 ffffffff81518af2 ffffffff81086962
[  113.487732]  ffff88001d538480 ffff88001d4c7ac8 ffffffff8107ae75 ffffffff8180a154
[  113.488628]  0000000000000b30 0000000000000000 00000000000000d0 ffff88001d4c7ad8
[  113.489525] Call Trace:
[  113.489813]  [<ffffffff81518af2>] dump_stack+0x4c/0x65
[  113.490389]  [<ffffffff81086962>] ? console_unlock+0x3d6/0x405
[  113.491039]  [<ffffffff8107ae75>] lockdep_rcu_suspicious+0xfa/0x103
[  113.491735]  [<ffffffff81064032>] rcu_preempt_sleep_check+0x45/0x47
[  113.492442]  [<ffffffff8106404d>] ___might_sleep+0x19/0x1c8
[  113.493077]  [<ffffffff81064268>] __might_sleep+0x6c/0x82
[  113.493681]  [<ffffffff81133190>] cache_alloc_debugcheck_before.isra.50+0x1d/0x24
[  113.494508]  [<ffffffff81134876>] kmem_cache_alloc+0x31/0x18f
[  113.495149]  [<ffffffff814012b5>] skb_clone+0x64/0x80
[  113.495712]  [<ffffffff814e6f71>] pfkey_broadcast_one+0x3d/0xff
[  113.496380]  [<ffffffff814e7b84>] pfkey_broadcast+0xb5/0x11e
[  113.497024]  [<ffffffff814e82d1>] pfkey_register+0x191/0x1b1
[  113.497653]  [<ffffffff814e9770>] pfkey_process+0x162/0x17e
[  113.498274]  [<ffffffff814e9895>] pfkey_sendmsg+0x109/0x213

In pfkey_sendmsg the net mutex is taken and then pfkey_broadcast takes
the RCU lock. Fix by using GFP_ATOMIC for the allocation flag.

Signed-off-by: David Ahern <dsa@...ulusnetworks.com>
---
 net/key/af_key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index b397f0aa9005..73527e7dd247 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1670,7 +1670,7 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad
 		return -ENOBUFS;
 	}
 
-	pfkey_broadcast(supp_skb, GFP_KERNEL, BROADCAST_REGISTERED, sk, sock_net(sk));
+	pfkey_broadcast(supp_skb, GFP_ATOMIC, BROADCAST_REGISTERED, sk, sock_net(sk));
 
 	return 0;
 }
-- 
2.3.2 (Apple Git-55)

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html