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| author | Zhenzhong Duan <zhenzhong.duan@gmail.com> | 2020-06-18 11:21:24 +0800 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2020-06-18 17:46:59 +0100 |
| commit | abd42781c3d2155868821f1b947ae45bbc33330d (patch) | |
| tree | eb27f5bb3c2d4720aa8832d9c1886eea08a21ed5 | |
| parent | 35700e221b18fa53401e5f315be90af9e0bbcdca (diff) | |
| download | sparc-next-abd42781c3d2155868821f1b947ae45bbc33330d.tar.gz | |
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>
| -rw-r--r-- | drivers/spi/spidev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index d753df700e9ea..f74ea26c382f2 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); |