diff options
| author |   Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2022-09-02 20:23:48 +0900 |
|---|---|---|
| committer |   Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2022-09-19 10:24:24 -0700 |
| commit | deee93d13d385103205879a8a0915036ecd83261 (patch) | |
| tree | 088ffbba0066f818a36861a74a91f3ef45989ba5 /net/bluetooth | |
| parent | Bluetooth: L2CAP: initialize delayed works at l2cap_chan_create() (diff) | |
| download | linux-dev-deee93d13d385103205879a8a0915036ecd83261.tar.xz linux-dev-deee93d13d385103205879a8a0915036ecd83261.zip | |
Bluetooth: use hdev->workqueue when queuing hdev->{cmd,ncmd}_timer works
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>
Diffstat (limited to 'net/bluetooth')
| -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 3803e54f23c0..66c7cdba0d32 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -597,6 +597,15 @@ 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); @@ -4063,12 +4072,14 @@ 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 5acb6fa6d676..ed3e5b251af1 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3767,16 +3767,18 @@ 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(); } static u8 hci_cc_le_read_buffer_size_v2(struct hci_dev *hdev, void *data, |