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authorZhenzhong Duan <zhenzhong.duan@gmail.com>2020-06-18 06:21:24 +0300
committerMark Brown <broonie@kernel.org>2020-06-18 19:46:59 +0300
commitabd42781c3d2155868821f1b947ae45bbc33330d (patch)
treeeb27f5bb3c2d4720aa8832d9c1886eea08a21ed5 /drivers/spi/spidev.c
parent35700e221b18fa53401e5f315be90af9e0bbcdca (diff)
downloadlinux-abd42781c3d2155868821f1b947ae45bbc33330d.tar.xz
spi: spidev: fix a race between spidev_release and spidev_remove
Imagine below scene, spidev is referenced after it's freed. spidev_release() spidev_remove() ... spin_lock_irq(&spidev->spi_lock); spidev->spi = NULL; spin_unlock_irq(&spidev->spi_lock); mutex_lock(&device_list_lock); dofree = (spidev->spi == NULL); if (dofree) kfree(spidev); mutex_unlock(&device_list_lock); mutex_lock(&device_list_lock); list_del(&spidev->device_entry); device_destroy(spidev_class, spidev->devt); clear_bit(MINOR(spidev->devt), minors); if (spidev->users == 0) kfree(spidev); mutex_unlock(&device_list_lock); Fix it by resetting spidev->spi in device_list_lock's protection. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com> Link: https://lore.kernel.org/r/20200618032125.4650-1-zhenzhong.duan@gmail.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spidev.c')
-rw-r--r--drivers/spi/spidev.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index d753df700e9e..f74ea26c382f 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -787,13 +787,13 @@ static int spidev_remove(struct spi_device *spi)
{
struct spidev_data *spidev = spi_get_drvdata(spi);
+ /* prevent new opens */
+ mutex_lock(&device_list_lock);
/* make sure ops on existing fds can abort cleanly */
spin_lock_irq(&spidev->spi_lock);
spidev->spi = NULL;
spin_unlock_irq(&spidev->spi_lock);
- /* prevent new opens */
- mutex_lock(&device_list_lock);
list_del(&spidev->device_entry);
device_destroy(spidev_class, spidev->devt);
clear_bit(MINOR(spidev->devt), minors);