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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2022-09-02 14:23:48 +0300
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2022-09-19 20:24:24 +0300
commitdeee93d13d385103205879a8a0915036ecd83261 (patch)
tree088ffbba0066f818a36861a74a91f3ef45989ba5 /net/bluetooth
parent2d2cb3066f2c90cd8ca540b36ba7a55e7f2406e0 (diff)
downloadlinux-deee93d13d385103205879a8a0915036ecd83261.tar.xz
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.c15
-rw-r--r--net/bluetooth/hci_event.c6
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,