From f68c224fedff2157f3fad7f7da674cbc96567c84 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 22 Apr 2010 16:06:59 -0700 Subject: [PATCH] dst: rcu check refinement __sk_dst_get() might be called from softirq, with socket lock held. [ 159.026180] include/net/sock.h:1200 invoked rcu_dereference_check() without protection! [ 159.026261] [ 159.026261] other info that might help us debug this: [ 159.026263] [ 159.026425] [ 159.026426] rcu_scheduler_active = 1, debug_locks = 0 [ 159.026552] 2 locks held by swapper/0: [ 159.026609] #0: (&icsk->icsk_retransmit_timer){+.-...}, at: [] run_timer_softirq+0x105/0x350 [ 159.026839] #1: (slock-AF_INET){+.-...}, at: [] tcp_write_timer+0x2f/0x1e0 [ 159.027063] [ 159.027064] stack backtrace: [ 159.027172] Pid: 0, comm: swapper Not tainted 2.6.34-rc5-03707-gde498c8-dirty #36 [ 159.027252] Call Trace: [ 159.027306] [] lockdep_rcu_dereference +0xaf/0xc0 [ 159.027411] [] tcp_current_mss+0xa7/0xb0 [ 159.027537] [] tcp_write_wakeup+0x89/0x190 [ 159.027600] [] tcp_send_probe0+0x16/0x100 [ 159.027726] [] tcp_write_timer+0x179/0x1e0 [ 159.027790] [] run_timer_softirq+0x191/0x350 [ 159.027980] [] __do_softirq+0xcd/0x200 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sock.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/net/sock.h b/include/net/sock.h index 8ab05146a447..86a8ca177a29 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1197,7 +1197,8 @@ static inline struct dst_entry * __sk_dst_get(struct sock *sk) { return rcu_dereference_check(sk->sk_dst_cache, rcu_read_lock_held() || - sock_owned_by_user(sk)); + sock_owned_by_user(sk) || + lockdep_is_held(&sk->sk_lock.slock)); } static inline struct dst_entry * -- 2.39.5