tcp: do not release socket ownership in tcp_close()
syzkaller was able to hit the WARN_ON(sock_owned_by_user(sk));
in tcp_close()
While a socket is being closed, it is very possible other
threads find it in rtnetlink dump.
tcp_get_info() will acquire the socket lock for a short amount
of time (slow = lock_sock_fast(sk)/unlock_sock_fast(sk, slow);),
enough to trigger the warning.
Fixes: 67db3e4bfb
("tcp: no longer hold ehash lock while calling tcp_get_info()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
744486d426
commit
8873c064d1
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@ -1492,6 +1492,7 @@ static inline void lock_sock(struct sock *sk)
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lock_sock_nested(sk, 0);
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lock_sock_nested(sk, 0);
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}
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}
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void __release_sock(struct sock *sk);
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void release_sock(struct sock *sk);
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void release_sock(struct sock *sk);
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/* BH context may only use the following locking interface. */
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/* BH context may only use the following locking interface. */
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@ -2317,7 +2317,7 @@ static void __lock_sock(struct sock *sk)
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finish_wait(&sk->sk_lock.wq, &wait);
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finish_wait(&sk->sk_lock.wq, &wait);
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}
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}
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static void __release_sock(struct sock *sk)
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void __release_sock(struct sock *sk)
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__releases(&sk->sk_lock.slock)
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__releases(&sk->sk_lock.slock)
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__acquires(&sk->sk_lock.slock)
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__acquires(&sk->sk_lock.slock)
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{
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{
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@ -2416,16 +2416,10 @@ adjudge_to_death:
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sock_hold(sk);
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sock_hold(sk);
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sock_orphan(sk);
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sock_orphan(sk);
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/* It is the last release_sock in its life. It will remove backlog. */
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release_sock(sk);
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/* Now socket is owned by kernel and we acquire BH lock
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* to finish close. No need to check for user refs.
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*/
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local_bh_disable();
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local_bh_disable();
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bh_lock_sock(sk);
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bh_lock_sock(sk);
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WARN_ON(sock_owned_by_user(sk));
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/* remove backlog if any, without releasing ownership. */
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__release_sock(sk);
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percpu_counter_inc(sk->sk_prot->orphan_count);
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percpu_counter_inc(sk->sk_prot->orphan_count);
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@ -2494,6 +2488,7 @@ adjudge_to_death:
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out:
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out:
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bh_unlock_sock(sk);
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bh_unlock_sock(sk);
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local_bh_enable();
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local_bh_enable();
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release_sock(sk);
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sock_put(sk);
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sock_put(sk);
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}
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}
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EXPORT_SYMBOL(tcp_close);
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EXPORT_SYMBOL(tcp_close);
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