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[RESEND,v2] Bluetooth: hci_uart: fix race during initialization

Message ID 3674b7a9-109e-19d7-4db8-02e9a724c314@salutedevices.com
State Accepted
Commit c411c62cc13319533b1861e00cedc4883c3bc1bb
Headers show
Series [RESEND,v2] Bluetooth: hci_uart: fix race during initialization | expand

Commit Message

Arseniy Krasnov Jan. 30, 2025, 6:43 p.m. UTC 
'hci_register_dev()' calls power up function, which is executed by
kworker - 'hci_power_on()'. This function does access to bluetooth chip
using callbacks from 'hci_ldisc.c', for example 'hci_uart_send_frame()'.
Now 'hci_uart_send_frame()' checks 'HCI_UART_PROTO_READY' bit set, and
if not - it fails. Problem is that 'HCI_UART_PROTO_READY' is set after
'hci_register_dev()', and there is tiny chance that 'hci_power_on()' will
be executed before setting this bit. In that case HCI init logic fails.

Patch moves setting of 'HCI_UART_PROTO_READY' before calling function
'hci_uart_register_dev()'.

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
---
 Changelog v1->v2:
 * Move 'set_bit()' before 'hci_uart_register_dev()' instead of
   adding new bit 'HCI_UART_PROTO_INIT'.

 drivers/bluetooth/hci_ldisc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

patchwork-bot+bluetooth@kernel.org Feb. 3, 2025, 9:40 p.m. UTC | #1 
Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Thu, 30 Jan 2025 21:43:26 +0300 you wrote:
> 'hci_register_dev()' calls power up function, which is executed by
> kworker - 'hci_power_on()'. This function does access to bluetooth chip
> using callbacks from 'hci_ldisc.c', for example 'hci_uart_send_frame()'.
> Now 'hci_uart_send_frame()' checks 'HCI_UART_PROTO_READY' bit set, and
> if not - it fails. Problem is that 'HCI_UART_PROTO_READY' is set after
> 'hci_register_dev()', and there is tiny chance that 'hci_power_on()' will
> be executed before setting this bit. In that case HCI init logic fails.
> 
> [...]

Here is the summary with links:
  - [RESEND,v2] Bluetooth: hci_uart: fix race during initialization
    https://git.kernel.org/bluetooth/bluetooth-next/c/c411c62cc133

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 30192bb083549..07b9aa09bbe2e 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -704,12 +704,13 @@  static int hci_uart_set_proto(struct hci_uart *hu, int id)
 
 	hu->proto = p;
 
+	set_bit(HCI_UART_PROTO_READY, &hu->flags);
+
 	err = hci_uart_register_dev(hu);
 	if (err) {
 		return err;
 	}
 
-	set_bit(HCI_UART_PROTO_READY, &hu->flags);
 	return 0;
 }