From: Simon Arlott <simon@xxxxxxxxxxx>
commit 7dd9c26bd6cf679bcfdef01a8659791aa6487a29 upstream.
The mcp251x_hw_wake() function is called with the mpc_lock mutex held and
disables the interrupt handler so that no interrupts can be processed while
waking the device. If an interrupt has already occurred then waiting for
the interrupt handler to complete will deadlock because it will be trying
to acquire the same mutex.
CPU0 CPU1
---- ----
mcp251x_open()
mutex_lock(&priv->mcp_lock)
request_threaded_irq()
<interrupt>
mcp251x_can_ist()
mutex_lock(&priv->mcp_lock)
mcp251x_hw_wake()
disable_irq() <-- deadlock
Use disable_irq_nosync() instead because the interrupt handler does
everything while holding the mutex so it doesn't matter if it's still
running.
Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
Signed-off-by: Simon Arlott <simon@xxxxxxxxxxx>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/4fc08687-1d80-43fe-9f0d-8ef8475e75f6@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/can/spi/mcp251x.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -755,7 +755,7 @@ static int mcp251x_hw_wake(struct spi_de
int ret;
/* Force wakeup interrupt to wake device, but don't execute IST */
- disable_irq(spi->irq);
+ disable_irq_nosync(spi->irq);
mcp251x_write_2regs(spi, CANINTE, CANINTE_WAKIE, CANINTF_WAKIF);
/* Wait for oscillator startup timer after wake up */
Patches currently in stable-queue which might be from simon@xxxxxxxxxxx are
queue-5.10/can-mcp251x-fix-deadlock-if-an-interrupt-occurs-during-mcp251x_open.patch
