diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2022-09-02 20:23:48 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-12 09:51:26 +0200 |
| commit | c4635cf3d845a7324c25c52d549b70c8bd7ad4c7 (patch) | |
| tree | e67e8ee86cac0bd220f93209e580d9112741e1dd | |
| parent | 6954cee8826819340594ef614341e4d634af3d4a (diff) | |
Bluetooth: use hdev->workqueue when queuing hdev->{cmd,ncmd}_timer works
commit deee93d13d385103205879a8a0915036ecd83261 upstream.
syzbot is reporting attempt to schedule hdev->cmd_work work from system_wq
WQ into hdev->workqueue WQ which is under draining operation [1], for
commit c8efcc2589464ac7 ("workqueue: allow chained queueing during
destruction") does not allow such operation.
The check introduced by commit 877afadad2dce8aa ("Bluetooth: When HCI work
queue is drained, only queue chained work") was incomplete.
Use hdev->workqueue WQ when queuing hdev->{cmd,ncmd}_timer works because
hci_{cmd,ncmd}_timeout() calls queue_work(hdev->workqueue). Also, protect
the queuing operation with RCU read lock in order to avoid calling
queue_delayed_work() after cancel_delayed_work() completed.
Link: https://syzkaller.appspot.com/bug?extid=243b7d89777f90f7613b [1]
Reported-by: syzbot <syzbot+243b7d89777f90f7613b@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 877afadad2dce8aa ("Bluetooth: When HCI work queue is drained, only queue chained work")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/bluetooth/hci_core.c | 15 | ||||
| -rw-r--r-- | net/bluetooth/hci_event.c | 6 |
2 files changed, 17 insertions, 4 deletions
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 6a53bcc5cfbb..48029a390c65 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -596,6 +596,15 @@ static int hci_dev_do_reset(struct hci_dev *hdev) /* Cancel these to avoid queueing non-chained pending work */ hci_dev_set_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE); + /* Wait for + * + * if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) + * queue_delayed_work(&hdev->{cmd,ncmd}_timer) + * + * inside RCU section to see the flag or complete scheduling. + */ + synchronize_rcu(); + /* Explicitly cancel works in case scheduled after setting the flag. */ cancel_delayed_work(&hdev->cmd_timer); cancel_delayed_work(&hdev->ncmd_timer); @@ -3871,12 +3880,14 @@ static void hci_cmd_work(struct work_struct *work) if (res < 0) __hci_cmd_sync_cancel(hdev, -res); + rcu_read_lock(); if (test_bit(HCI_RESET, &hdev->flags) || hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) cancel_delayed_work(&hdev->cmd_timer); else - schedule_delayed_work(&hdev->cmd_timer, - HCI_CMD_TIMEOUT); + queue_delayed_work(hdev->workqueue, &hdev->cmd_timer, + HCI_CMD_TIMEOUT); + rcu_read_unlock(); } else { skb_queue_head(&hdev->cmd_q, skb); queue_work(hdev->workqueue, &hdev->cmd_work); diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 2c320a8fe70d..81e5bcdbbe94 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3763,16 +3763,18 @@ static inline void handle_cmd_cnt_and_timer(struct hci_dev *hdev, u8 ncmd) { cancel_delayed_work(&hdev->cmd_timer); + rcu_read_lock(); if (!test_bit(HCI_RESET, &hdev->flags)) { if (ncmd) { cancel_delayed_work(&hdev->ncmd_timer); atomic_set(&hdev->cmd_cnt, 1); } else { if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) - schedule_delayed_work(&hdev->ncmd_timer, - HCI_NCMD_TIMEOUT); + queue_delayed_work(hdev->workqueue, &hdev->ncmd_timer, + HCI_NCMD_TIMEOUT); } } + rcu_read_unlock(); } #define HCI_CC_VL(_op, _func, _min, _max) \ |