* 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
@ 2012-03-07 13:25 Valdis.Kletnieks
2012-03-07 14:31 ` Eric Dumazet
2012-03-07 14:45 ` Eric Dumazet
0 siblings, 2 replies; 4+ messages in thread
From: Valdis.Kletnieks @ 2012-03-07 13:25 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 2243 bytes --]
Seen in my dmesg. Dell Latitude E6500.
[ 164.842511]
[ 164.842522] ===============================
[ 164.842528] [ INFO: suspicious RCU usage. ]
[ 164.842538] 3.3.0-rc6-next-20120305 #1 Tainted: G O
[ 164.842544] -------------------------------
[ 164.842552] net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
[ 164.842559]
[ 164.842560] other info that might help us debug this:
[ 164.842563]
[ 164.842570]
[ 164.842571] rcu_scheduler_active = 1, debug_locks = 1
[ 164.842579] 2 locks held by ksoftirqd/1/10:
[ 164.842586] #0: (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81039086>] run_timer_softirq+0x17f/0x3e7
[ 164.842620] #1: (slock-AF_INET){+.-...}, at: [<ffffffff814b75b3>] tcp_write_timer+0x1a/0x17b
[ 164.842649]
[ 164.842651] stack backtrace:
[ 164.842660] Pid: 10, comm: ksoftirqd/1 Tainted: G O 3.3.0-rc6-next-20120305 #1
[ 164.842668] Call Trace:
[ 164.842685] [<ffffffff8106e6a2>] lockdep_rcu_suspicious+0xec/0xf5
[ 164.842698] [<ffffffff814b7f40>] tcp_md5_do_lookup+0x60/0xbe
[ 164.842710] [<ffffffff814b7fc0>] tcp_v4_md5_lookup+0xe/0x10
[ 164.842725] [<ffffffff814b2eb5>] tcp_established_options+0x32/0x110
[ 164.842739] [<ffffffff814b42d7>] tcp_current_mss+0x50/0x6f
[ 164.842753] [<ffffffff814b5c50>] tcp_retransmit_skb+0xa9/0x510
[ 164.842766] [<ffffffff814ab727>] ? tcp_set_ca_state+0x23/0x2f
[ 164.842779] [<ffffffff814b73ee>] tcp_retransmit_timer+0x376/0x521
[ 164.842791] [<ffffffff814b7638>] tcp_write_timer+0x9f/0x17b
[ 164.842804] [<ffffffff8103915e>] run_timer_softirq+0x257/0x3e7
[ 164.842816] [<ffffffff81039086>] ? run_timer_softirq+0x17f/0x3e7
[ 164.842828] [<ffffffff814b7599>] ? tcp_retransmit_timer+0x521/0x521
[ 164.842843] [<ffffffff81032207>] __do_softirq+0x10a/0x25f
[ 164.842857] [<ffffffff81032411>] run_ksoftirqd+0xb5/0x200
[ 164.842869] [<ffffffff8103235c>] ? __do_softirq+0x25f/0x25f
[ 164.842884] [<ffffffff810499bd>] kthread+0x86/0x8e
[ 164.842900] [<ffffffff815e2434>] kernel_thread_helper+0x4/0x10
[ 164.842914] [<ffffffff815db41d>] ? retint_restore_args+0xe/0xe
[ 164.842928] [<ffffffff81049937>] ? flush_kthread_worker+0xcf/0xcf
[ 164.842941] [<ffffffff815e2430>] ? gs_change+0xb/0xb
[-- Attachment #2: Type: application/pgp-signature, Size: 865 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
2012-03-07 13:25 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage! Valdis.Kletnieks
@ 2012-03-07 14:31 ` Eric Dumazet
2012-03-07 14:45 ` Eric Dumazet
1 sibling, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2012-03-07 14:31 UTC (permalink / raw)
To: Valdis.Kletnieks; +Cc: David S. Miller, netdev, linux-kernel
Le mercredi 07 mars 2012 à 08:25 -0500, Valdis.Kletnieks@vt.edu a
écrit :
> Seen in my dmesg. Dell Latitude E6500.
>
> [ 164.842511]
> [ 164.842522] ===============================
> [ 164.842528] [ INFO: suspicious RCU usage. ]
> [ 164.842538] 3.3.0-rc6-next-20120305 #1 Tainted: G O
> [ 164.842544] -------------------------------
> [ 164.842552] net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
> [ 164.842559]
> [ 164.842560] other info that might help us debug this:
> [ 164.842563]
> [ 164.842570]
> [ 164.842571] rcu_scheduler_active = 1, debug_locks = 1
> [ 164.842579] 2 locks held by ksoftirqd/1/10:
> [ 164.842586] #0: (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81039086>] run_timer_softirq+0x17f/0x3e7
> [ 164.842620] #1: (slock-AF_INET){+.-...}, at: [<ffffffff814b75b3>] tcp_write_timer+0x1a/0x17b
> [ 164.842649]
> [ 164.842651] stack backtrace:
> [ 164.842660] Pid: 10, comm: ksoftirqd/1 Tainted: G O 3.3.0-rc6-next-20120305 #1
> [ 164.842668] Call Trace:
> [ 164.842685] [<ffffffff8106e6a2>] lockdep_rcu_suspicious+0xec/0xf5
> [ 164.842698] [<ffffffff814b7f40>] tcp_md5_do_lookup+0x60/0xbe
> [ 164.842710] [<ffffffff814b7fc0>] tcp_v4_md5_lookup+0xe/0x10
> [ 164.842725] [<ffffffff814b2eb5>] tcp_established_options+0x32/0x110
> [ 164.842739] [<ffffffff814b42d7>] tcp_current_mss+0x50/0x6f
> [ 164.842753] [<ffffffff814b5c50>] tcp_retransmit_skb+0xa9/0x510
> [ 164.842766] [<ffffffff814ab727>] ? tcp_set_ca_state+0x23/0x2f
> [ 164.842779] [<ffffffff814b73ee>] tcp_retransmit_timer+0x376/0x521
> [ 164.842791] [<ffffffff814b7638>] tcp_write_timer+0x9f/0x17b
> [ 164.842804] [<ffffffff8103915e>] run_timer_softirq+0x257/0x3e7
> [ 164.842816] [<ffffffff81039086>] ? run_timer_softirq+0x17f/0x3e7
> [ 164.842828] [<ffffffff814b7599>] ? tcp_retransmit_timer+0x521/0x521
> [ 164.842843] [<ffffffff81032207>] __do_softirq+0x10a/0x25f
> [ 164.842857] [<ffffffff81032411>] run_ksoftirqd+0xb5/0x200
> [ 164.842869] [<ffffffff8103235c>] ? __do_softirq+0x25f/0x25f
> [ 164.842884] [<ffffffff810499bd>] kthread+0x86/0x8e
> [ 164.842900] [<ffffffff815e2434>] kernel_thread_helper+0x4/0x10
> [ 164.842914] [<ffffffff815db41d>] ? retint_restore_args+0xe/0xe
> [ 164.842928] [<ffffffff81049937>] ? flush_kthread_worker+0xcf/0xcf
> [ 164.842941] [<ffffffff815e2430>] ? gs_change+0xb/0xb
>
Thanks for the report, I'll submit a patch in a few minutes
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
2012-03-07 13:25 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage! Valdis.Kletnieks
2012-03-07 14:31 ` Eric Dumazet
@ 2012-03-07 14:45 ` Eric Dumazet
2012-03-07 20:16 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Eric Dumazet @ 2012-03-07 14:45 UTC (permalink / raw)
To: Valdis.Kletnieks; +Cc: David S. Miller, netdev, linux-kernel
Le mercredi 07 mars 2012 à 08:25 -0500, Valdis.Kletnieks@vt.edu a
écrit :
> Seen in my dmesg. Dell Latitude E6500.
>
> [ 164.842511]
> [ 164.842522] ===============================
> [ 164.842528] [ INFO: suspicious RCU usage. ]
> [ 164.842538] 3.3.0-rc6-next-20120305 #1 Tainted: G O
> [ 164.842544] -------------------------------
> [ 164.842552] net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
> [ 164.842559]
> [ 164.842560] other info that might help us debug this:
> [ 164.842563]
> [ 164.842570]
> [ 164.842571] rcu_scheduler_active = 1, debug_locks = 1
> [ 164.842579] 2 locks held by ksoftirqd/1/10:
> [ 164.842586] #0: (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81039086>] run_timer_softirq+0x17f/0x3e7
> [ 164.842620] #1: (slock-AF_INET){+.-...}, at: [<ffffffff814b75b3>] tcp_write_timer+0x1a/0x17b
> [ 164.842649]
> [ 164.842651] stack backtrace:
> [ 164.842660] Pid: 10, comm: ksoftirqd/1 Tainted: G O 3.3.0-rc6-next-20120305 #1
> [ 164.842668] Call Trace:
> [ 164.842685] [<ffffffff8106e6a2>] lockdep_rcu_suspicious+0xec/0xf5
> [ 164.842698] [<ffffffff814b7f40>] tcp_md5_do_lookup+0x60/0xbe
> [ 164.842710] [<ffffffff814b7fc0>] tcp_v4_md5_lookup+0xe/0x10
> [ 164.842725] [<ffffffff814b2eb5>] tcp_established_options+0x32/0x110
> [ 164.842739] [<ffffffff814b42d7>] tcp_current_mss+0x50/0x6f
> [ 164.842753] [<ffffffff814b5c50>] tcp_retransmit_skb+0xa9/0x510
> [ 164.842766] [<ffffffff814ab727>] ? tcp_set_ca_state+0x23/0x2f
> [ 164.842779] [<ffffffff814b73ee>] tcp_retransmit_timer+0x376/0x521
> [ 164.842791] [<ffffffff814b7638>] tcp_write_timer+0x9f/0x17b
> [ 164.842804] [<ffffffff8103915e>] run_timer_softirq+0x257/0x3e7
> [ 164.842816] [<ffffffff81039086>] ? run_timer_softirq+0x17f/0x3e7
> [ 164.842828] [<ffffffff814b7599>] ? tcp_retransmit_timer+0x521/0x521
> [ 164.842843] [<ffffffff81032207>] __do_softirq+0x10a/0x25f
> [ 164.842857] [<ffffffff81032411>] run_ksoftirqd+0xb5/0x200
> [ 164.842869] [<ffffffff8103235c>] ? __do_softirq+0x25f/0x25f
> [ 164.842884] [<ffffffff810499bd>] kthread+0x86/0x8e
> [ 164.842900] [<ffffffff815e2434>] kernel_thread_helper+0x4/0x10
> [ 164.842914] [<ffffffff815db41d>] ? retint_restore_args+0xe/0xe
> [ 164.842928] [<ffffffff81049937>] ? flush_kthread_worker+0xcf/0xcf
> [ 164.842941] [<ffffffff815e2430>] ? gs_change+0xb/0xb
>
[PATCH net-next] tcp: md5: correct a RCU lockdep splat
commit a8afca0329 (tcp: md5: protects md5sig_info with RCU) added a
lockdep splat in tcp_md5_do_lookup() in case a timer fires a tcp
retransmit.
At this point, socket lock is owned by the sofirq handler, not the user,
so we should adjust a bit the lockdep condition, as we dont hold
rcu_read_lock().
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
---
net/ipv4/tcp_ipv4.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 94abee8..507924b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -927,7 +927,8 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
/* caller either holds rcu_read_lock() or socket lock */
md5sig = rcu_dereference_check(tp->md5sig_info,
- sock_owned_by_user(sk));
+ sock_owned_by_user(sk) ||
+ lockdep_is_held(&sk->sk_lock.slock));
if (!md5sig)
return NULL;
#if IS_ENABLED(CONFIG_IPV6)
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage!
2012-03-07 14:45 ` Eric Dumazet
@ 2012-03-07 20:16 ` David Miller
0 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2012-03-07 20:16 UTC (permalink / raw)
To: eric.dumazet; +Cc: Valdis.Kletnieks, netdev, linux-kernel
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 07 Mar 2012 06:45:43 -0800
> [PATCH net-next] tcp: md5: correct a RCU lockdep splat
>
> commit a8afca0329 (tcp: md5: protects md5sig_info with RCU) added a
> lockdep splat in tcp_md5_do_lookup() in case a timer fires a tcp
> retransmit.
>
> At this point, socket lock is owned by the sofirq handler, not the user,
> so we should adjust a bit the lockdep condition, as we dont hold
> rcu_read_lock().
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Applied, thanks Eric.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-03-07 13:25 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage! Valdis.Kletnieks
2012-03-07 14:31 ` Eric Dumazet
2012-03-07 14:45 ` Eric Dumazet
2012-03-07 20:16 ` David Miller
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