=============================================
[ 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 <[email protected]>
---
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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