diff options
| author | Ying Hsu <yinghsu@chromium.org> | 2023-09-04 17:11:51 +0300 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2023-09-20 21:01:42 +0300 |
| commit | c7eaf80bfb0c8cef852cce9501b95dd5a6bddcb9 (patch) | |
| tree | d1a898c8c7445758789744c79453a6823d0687d2 | |
| parent | 941c998b42f5c90384f49da89a6e11233de567cf (diff) | |
| download | linux-c7eaf80bfb0c8cef852cce9501b95dd5a6bddcb9.tar.xz | |
Bluetooth: Fix hci_link_tx_to RCU lock usage
Syzbot found a bug "BUG: sleeping function called from invalid context
at kernel/locking/mutex.c:580". It is because hci_link_tx_to holds an
RCU read lock and calls hci_disconnect which would hold a mutex lock
since the commit a13f316e90fd ("Bluetooth: hci_conn: Consolidate code
for aborting connections"). Here's an example call trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xfc/0x174 lib/dump_stack.c:106
___might_sleep+0x4a9/0x4d3 kernel/sched/core.c:9663
__mutex_lock_common kernel/locking/mutex.c:576 [inline]
__mutex_lock+0xc7/0x6e7 kernel/locking/mutex.c:732
hci_cmd_sync_queue+0x3a/0x287 net/bluetooth/hci_sync.c:388
hci_abort_conn+0x2cd/0x2e4 net/bluetooth/hci_conn.c:1812
hci_disconnect+0x207/0x237 net/bluetooth/hci_conn.c:244
hci_link_tx_to net/bluetooth/hci_core.c:3254 [inline]
__check_timeout net/bluetooth/hci_core.c:3419 [inline]
__check_timeout+0x310/0x361 net/bluetooth/hci_core.c:3399
hci_sched_le net/bluetooth/hci_core.c:3602 [inline]
hci_tx_work+0xe8f/0x12d0 net/bluetooth/hci_core.c:3652
process_one_work+0x75c/0xba1 kernel/workqueue.c:2310
worker_thread+0x5b2/0x73a kernel/workqueue.c:2457
kthread+0x2f7/0x30b kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
This patch releases RCU read lock before calling hci_disconnect and
reacquires it afterward to fix the bug.
Fixes: a13f316e90fd ("Bluetooth: hci_conn: Consolidate code for aborting connections")
Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
| -rw-r--r-- | net/bluetooth/hci_core.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index a5992f1b3c9b..db4f28d68d71 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3418,7 +3418,12 @@ static void hci_link_tx_to(struct hci_dev *hdev, __u8 type) if (c->type == type && c->sent) { bt_dev_err(hdev, "killing stalled connection %pMR", &c->dst); + /* hci_disconnect might sleep, so, we have to release + * the RCU read lock before calling it. + */ + rcu_read_unlock(); hci_disconnect(c, HCI_ERROR_REMOTE_USER_TERM); + rcu_read_lock(); } } |