From f7ab9e14b23a3eac6714bdc4dba244d8aa1ef646 Mon Sep 17 00:00:00 2001 From: Simon Arlott Date: Thu, 22 Aug 2024 08:25:07 +0100 Subject: [PATCH] can: mcp251x: fix deadlock if an interrupt occurs during mcp251x_open 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() 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 Reviewed-by: Przemek Kitszel 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 Signed-off-by: Greg Kroah-Hartman --- drivers/net/can/spi/mcp251x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c index 79c4bab5f724..8c56f85e87c1 100644 --- a/drivers/net/can/spi/mcp251x.c +++ b/drivers/net/can/spi/mcp251x.c @@ -753,7 +753,7 @@ 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 */