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| author | Satyam Sharma <ssatyam@cse.iitk.ac.in> | 2007-05-16 23:50:16 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-05-17 14:20:30 -0700 |
| commit | 4ce61d1c7a8ef4c1337fa983a3036d4010e3c19e (patch) | |
| tree | e7bf734478bc3f726d883439d5fdc44699d9a20a /net/bluetooth | |
| parent | 689d79469b64662440a93ffbd1cbf994510bcbf6 (diff) | |
| download | linux-4ce61d1c7a8ef4c1337fa983a3036d4010e3c19e.tar.gz linux-4ce61d1c7a8ef4c1337fa983a3036d4010e3c19e.tar.bz2 linux-4ce61d1c7a8ef4c1337fa983a3036d4010e3c19e.zip | |
[BLUETOOTH]: Fix locking in hci_sock_dev_event().
We presently use lock_sock() to acquire a lock on a socket in
hci_sock_dev_event(), but this goes BUG because lock_sock()
can sleep and we're already holding a read-write spinlock at
that point. So, we must use the non-sleeping BH version,
bh_lock_sock().
However, hci_sock_dev_event() is called from user context and
hence using simply bh_lock_sock() will deadlock against a
concurrent softirq that tries to acquire a lock on the same
socket. Hence, disabling BH's before acquiring the socket lock
and enable them afterwards, is the proper solution to fix
socket locking in hci_sock_dev_event().
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bluetooth')
| -rw-r--r-- | net/bluetooth/hci_sock.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index bfc9a35bad33..1dae3dfc66a9 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -665,7 +665,8 @@ static int hci_sock_dev_event(struct notifier_block *this, unsigned long event, /* Detach sockets from device */ read_lock(&hci_sk_list.lock); sk_for_each(sk, node, &hci_sk_list.head) { - lock_sock(sk); + local_bh_disable(); + bh_lock_sock_nested(sk); if (hci_pi(sk)->hdev == hdev) { hci_pi(sk)->hdev = NULL; sk->sk_err = EPIPE; @@ -674,7 +675,8 @@ static int hci_sock_dev_event(struct notifier_block *this, unsigned long event, hci_dev_put(hdev); } - release_sock(sk); + bh_unlock_sock(sk); + local_bh_enable(); } read_unlock(&hci_sk_list.lock); } |