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[net,12/13] can: mcp251x: fix deadlock if an interrupt occurs during mcp251x_open

Message ID 20240830215914.1610393-13-mkl@pengutronix.de (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series [net,0/n] pull-request: can 2024-08-30 | expand

Commit Message

Marc Kleine-Budde Aug. 30, 2024, 9:53 p.m. UTC 
From: Simon Arlott <simon@octiron.net>

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@octiron.net>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/4fc08687-1d80-43fe-9f0d-8ef8475e75f6@0882a8b5-c6c3-11e9-b005-00805fc181fe.uuid.home.arpa
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/spi/mcp251x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 3b8736ff0345..ec5c64006a16 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -752,7 +752,7 @@  static int mcp251x_hw_wake(struct spi_device *spi)
 	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 */