spi: spidev: fix possible NULL dereference

During the last close we are freeing spidev if spidev->spi is NULL, but
just before checking if spidev->spi is NULL we are dereferencing it.
Lets add a check there to avoid the NULL dereference.

Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying spi device")
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index dd616ff0ffc5..e58ca17eb247 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -651,7 +651,8 @@ static int spidev_release(struct inode *inode, struct file *filp)
                 kfree(spidev->rx_buffer);
                 spidev->rx_buffer = NULL;
 
-                spidev->speed_hz = spidev->spi->max_speed_hz;
+                if (spidev->spi)
+                        spidev->speed_hz = spidev->spi->max_speed_hz;
 
                 /* ... after we unbound from the underlying device? */
                 spin_lock_irq(&spidev->spi_lock);