Messages in this thread Patch in this message | | | Subject | [PATCH] lockdep: annotate sk_lock nesting in AF_BLUETOOTH | From | Peter Zijlstra <> | Date | Mon, 30 Oct 2006 09:16:26 +0100 |
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============================================= [ INFO: possible recursive locking detected ] 2.6.18-1.2726.fc6 #1 --------------------------------------------- hidd/2271 is trying to acquire lock: (sk_lock-AF_BLUETOOTH){--..}, at: [<f8d16241>] bt_accept_dequeue+0x26/0xc6 [bluetooth]
but task is already holding lock: (sk_lock-AF_BLUETOOTH){--..}, at: [<f8bce088>] l2cap_sock_accept+0x41/0x11e [l2cap]
other info that might help us debug this: 1 lock held by hidd/2271: #0: (sk_lock-AF_BLUETOOTH){--..}, at: [<f8bce088>] l2cap_sock_accept+0x41/0x11e [l2cap]
stack backtrace: [<c04051ed>] show_trace_log_lvl+0x58/0x16a [<c04057fa>] show_trace+0xd/0x10 [<c0405913>] dump_stack+0x19/0x1b [<c043b7dc>] __lock_acquire+0x6ea/0x90d [<c043bf70>] lock_acquire+0x4b/0x6b [<c05b203b>] lock_sock+0xac/0xbc [<f8d16241>] bt_accept_dequeue+0x26/0xc6 [bluetooth] [<f8bce129>] l2cap_sock_accept+0xe2/0x11e [l2cap] [<c05b142e>] sys_accept+0xd8/0x179 [<c05b1576>] sys_socketcall+0xa7/0x186 [<c0403fb7>] syscall_call+0x7/0xb
classical case of nesting; bt_accept_dequeue() locks the children of the object locked by l2cap_sock_accept().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> --- include/net/sock.h | 13 ++++++++++++- net/bluetooth/l2cap.c | 2 +- net/core/sock.c | 6 +++--- 3 files changed, 16 insertions(+), 5 deletions(-)
Index: linux-2.6/include/net/sock.h =================================================================== --- linux-2.6.orig/include/net/sock.h +++ linux-2.6/include/net/sock.h @@ -745,7 +745,18 @@ static inline int sk_stream_wmem_schedul */ #define sock_owned_by_user(sk) ((sk)->sk_lock.owner) -extern void FASTCALL(lock_sock(struct sock *sk)); +extern void FASTCALL(_lock_sock(struct sock *sk, int subclass)); + +static inline void lock_sock(struct sock *sk) +{ + _lock_sock(sk, 0); +} + +static inline void lock_sock_nested(struct sock *sk, int subclass) +{ + _lock_sock(sk, subclass); +} + extern void FASTCALL(release_sock(struct sock *sk)); /* BH context may only use the following locking interface. */ Index: linux-2.6/net/bluetooth/l2cap.c =================================================================== --- linux-2.6.orig/net/bluetooth/l2cap.c +++ linux-2.6/net/bluetooth/l2cap.c @@ -770,7 +770,7 @@ static int l2cap_sock_accept(struct sock long timeo; int err = 0; - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); if (sk->sk_state != BT_LISTEN) { err = -EBADFD; Index: linux-2.6/net/core/sock.c =================================================================== --- linux-2.6.orig/net/core/sock.c +++ linux-2.6/net/core/sock.c @@ -1527,7 +1527,7 @@ void sock_init_data(struct socket *sock, atomic_set(&sk->sk_refcnt, 1); } -void fastcall lock_sock(struct sock *sk) +void fastcall _lock_sock(struct sock *sk, int subclass) { might_sleep(); spin_lock_bh(&sk->sk_lock.slock); @@ -1538,11 +1538,11 @@ void fastcall lock_sock(struct sock *sk) /* * The sk_lock has mutex_lock() semantics here: */ - mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_); + mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_); local_bh_enable(); } -EXPORT_SYMBOL(lock_sock); +EXPORT_SYMBOL(_lock_sock); void fastcall release_sock(struct sock *sk) {
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