[PATCH] can: hi311x: drop hi3110_lock before free_irq() on open failure

[Runyu Xiao]

hi3110_open() requests a threaded IRQ and then performs hardware
setup while holding priv->hi3110_lock. If reset, setup, or
normal-mode entry fails, the error path calls free_irq() while still
holding that mutex.

The threaded handler takes priv->hi3110_lock before checking
force_quit, while free_irq() waits for the threaded handler to finish.
That can deadlock the open() rollback path against a pending IRQ
thread.

Set force_quit, drop hi3110_lock before free_irq(), and take the
mutex again for the remaining hardware cleanup.

Fixes: 57e83fb9b746 ("can: hi311x: Add Holt HI-311x CAN driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>
---
 drivers/net/can/spi/hi311x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
index ae90e6716de5..2be851e8907d 100644
--- a/drivers/net/can/spi/hi311x.c
+++ b/drivers/net/can/spi/hi311x.c
@@ -787,7 +787,10 @@ static int hi3110_open(struct net_device *net)
 	return 0;
 
  out_free_irq:
+	priv->force_quit = 1;
+	mutex_unlock(&priv->hi3110_lock);
 	free_irq(spi->irq, priv);
+	mutex_lock(&priv->hi3110_lock);
 	hi3110_hw_sleep(spi);
  out_close:
 	hi3110_power_enable(priv->transceiver, 0);
-- 
2.34.1