[PATCH 6.18 294/396] i2c: imx: Cancel hrtimer before clearing slave pointer

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liem <[email protected]>

commit 6ac7702b6cc2b94aaed9ef2d95bfbefcdc90061f upstream.

In i2c_imx_unreg_slave(), the slave pointer is set to NULL after
disabling interrupts.  However, a pending interrupt might already
have started the hrtimer (i2c_imx_slave_timeout) before the pointer
was cleared.  If the hrtimer fires after i2c_imx->slave is set to
NULL, the timer callback i2c_imx_slave_finish_op() will call
i2c_imx_slave_event() with a NULL slave pointer, which results in a
use-after-free / NULL pointer dereference.

Fix by canceling the hrtimer and waiting for it to complete after
disabling interrupts, before clearing the slave pointer.

Fixes: f7414cd6923f ("i2c: imx: support slave mode for imx I2C driver")
Signed-off-by: Liem <[email protected]>
Cc: <[email protected]> # v5.11+
Acked-by: Carlos Song <[email protected]>
Reviewed-by: Frank Li <[email protected]>
Signed-off-by: Andi Shyti <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/i2c/busses/i2c-imx.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -960,6 +960,7 @@ static int i2c_imx_unreg_slave(struct i2
 
 	i2c_imx_reset_regs(i2c_imx);
 
+	hrtimer_cancel(&i2c_imx->slave_timer);
 	i2c_imx->slave = NULL;
 
 	/* Suspend */