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| author | Claire Chang <tientzu@chromium.org> | 2020-12-14 15:29:21 +0800 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2020-12-18 22:25:30 +0100 |
| commit | afe0b1c86458f121b085271e4f3034017a90d4a3 (patch) | |
| tree | bae859cd58fa412d934a0d5b8571984ec25e65f4 | |
| parent | c0187b0bd3e94c48050687d87b2c3c9fbae98ae9 (diff) | |
| download | linux-afe0b1c86458f121b085271e4f3034017a90d4a3.tar.gz linux-afe0b1c86458f121b085271e4f3034017a90d4a3.tar.bz2 linux-afe0b1c86458f121b085271e4f3034017a90d4a3.zip | |
Bluetooth: hci_uart: Fix a race for write_work scheduling
In hci_uart_write_work, there is a loop/goto checking the value of
HCI_UART_TX_WAKEUP. If HCI_UART_TX_WAKEUP is set again, it keeps trying
hci_uart_dequeue; otherwise, it clears HCI_UART_SENDING and returns.
In hci_uart_tx_wakeup, if HCI_UART_SENDING is already set, it sets
HCI_UART_TX_WAKEUP, skips schedule_work and assumes the running/pending
hci_uart_write_work worker will do hci_uart_dequeue properly.
However, if the HCI_UART_SENDING check in hci_uart_tx_wakeup is done after
the loop breaks, but before HCI_UART_SENDING is cleared in
hci_uart_write_work, the schedule_work is skipped incorrectly.
Fix this race by changing the order of HCI_UART_SENDING and
HCI_UART_TX_WAKEUP modification.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 82f5169bf3d3 ("Bluetooth: hci_uart: add serdev driver support library")
Signed-off-by: Claire Chang <tientzu@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | drivers/bluetooth/hci_ldisc.c | 7 | ||||
| -rw-r--r-- | drivers/bluetooth/hci_serdev.c | 4 |
2 files changed, 5 insertions, 6 deletions
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index f83d67eafc9f..8be4d807d137 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -127,10 +127,9 @@ int hci_uart_tx_wakeup(struct hci_uart *hu) if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) goto no_schedule; - if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) { - set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); + set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state); + if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) goto no_schedule; - } BT_DBG(""); @@ -174,10 +173,10 @@ restart: kfree_skb(skb); } + clear_bit(HCI_UART_SENDING, &hu->tx_state); if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)) goto restart; - clear_bit(HCI_UART_SENDING, &hu->tx_state); wake_up_bit(&hu->tx_state, HCI_UART_SENDING); } diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c index ef96ad06fa54..9e03402ef1b3 100644 --- a/drivers/bluetooth/hci_serdev.c +++ b/drivers/bluetooth/hci_serdev.c @@ -83,9 +83,9 @@ static void hci_uart_write_work(struct work_struct *work) hci_uart_tx_complete(hu, hci_skb_pkt_type(skb)); kfree_skb(skb); } - } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)); - clear_bit(HCI_UART_SENDING, &hu->tx_state); + clear_bit(HCI_UART_SENDING, &hu->tx_state); + } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)); } /* ------- Interface to HCI layer ------ */ |