From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx> Check that socket sk is not locked in user process before removing l2cap connection handler. krfcommd kernel thread may be preempted with l2cap tasklet which remove l2cap_conn structure. If krfcommd is in process of sending of RFCOMM reply (like "RFCOMM UA" reply to "RFCOMM DISC") then kernel crash happens. ... [ 694.175933] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 694.184936] pgd = c0004000 [ 694.187683] [00000000] *pgd=00000000 [ 694.191711] Internal error: Oops: 5 [#1] PREEMPT [ 694.196350] last sysfs file: /sys/devices/platform/hci_h4p/firmware/hci_h4p/loading [ 694.260375] CPU: 0 Not tainted (2.6.32.10 #1) [ 694.265106] PC is at l2cap_sock_sendmsg+0x43c/0x73c [l2cap] [ 694.270721] LR is at 0xd7017303 ... [ 694.525085] Backtrace: [ 694.527587] [<bf266be0>] (l2cap_sock_sendmsg+0x0/0x73c [l2cap]) from [<c02f2cc8>] (sock_sendmsg+0xb8/0xd8) [ 694.537292] [<c02f2c10>] (sock_sendmsg+0x0/0xd8) from [<c02f3044>] (kernel_sendmsg+0x48/0x80) ... Modified version after comments of Gustavo F. Padovan <gustavo@xxxxxxxxxxx> Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx> --- net/bluetooth/l2cap.c | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index bb00015..794f2b7 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -2927,7 +2927,9 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd break; default: - l2cap_chan_del(sk, ECONNREFUSED); + /* delete l2cap channel if sk is not owned by user */ + if (!sock_owned_by_user(sk)) + l2cap_chan_del(sk, ECONNREFUSED); break; } @@ -3135,7 +3137,10 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd del_timer(&l2cap_pi(sk)->ack_timer); } - l2cap_chan_del(sk, ECONNRESET); + /* delete l2cap channel if sk is not owned by user */ + if (!sock_owned_by_user(sk)) + l2cap_chan_del(sk, ECONNRESET); + bh_unlock_sock(sk); l2cap_sock_kill(sk); @@ -3167,7 +3172,10 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd del_timer(&l2cap_pi(sk)->ack_timer); } - l2cap_chan_del(sk, 0); + /* delete l2cap channel if sk is not owned by user */ + if (!sock_owned_by_user(sk)) + l2cap_chan_del(sk, 0); + bh_unlock_sock(sk); l2cap_sock_kill(sk); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
