spi: spidev: fix possible NULL dereference

commit dd85ebf681ef0ee1fc985c353dd45e8b53b5dc1e upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 92c909eed6b504b01086e4775143128069f33261..8fab566e0f0bc7e6b1a677250cf9051b1aa26052 100644 (file)
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -664,7 +664,8 @@ 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);