syzbot is hitting use-after-free bug in uinput module [1]. This is because uinput_destroy_device() sometimes kfree()s dev->name and dev->phys at uinput_destroy_device() before dev_uevent() is triggered by dropping the refcount to 0. Since the timing of triggering last input_put_device() is uncontrollable, this patch prepares for such race by setting dev->name and dev->phys to NULL before doing operations which might drop the refcount to 0.
[1] https://syzkaller.appspot.com/bug?id=8b17c134fe938bbddd75a45afaa9e68af43a362d Reported-by: syzbot <[email protected]> Signed-off-by: Tetsuo Handa <[email protected]> --- drivers/input/misc/uinput.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..131591b5babd 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -300,7 +300,9 @@ static void uinput_destroy_device(struct uinput_device *udev) if (dev) { name = dev->name; + dev->name = NULL; phys = dev->phys; + dev->phys = NULL; if (old_state == UIST_CREATED) { uinput_flush_requests(udev); input_unregister_device(dev); -- 2.17.1
