[PATCH 5.7 062/204] driver core: Avoid binding drivers to dead devices

Greg Kroah-Hartman
2020-08-20T13:05:08Z

From: Lukas Wunner <lukas@wunner.de>

commit 654888327e9f655a9d55ad477a9583e90e8c9b5c upstream.

Commit 3451a495ef24 ("driver core: Establish order of operations for
device_add and device_del via bitflag") sought to prevent asynchronous
driver binding to a device which is being removed. It added a
per-device "dead" flag which is checked in the following code paths:

* asynchronous binding in __driver_attach_async_helper()
* synchronous binding in device_driver_attach()
* asynchronous binding in __device_attach_async_helper()

It did *not* check the flag upon:

* synchronous binding in __device_attach()

However __device_attach() may also be called asynchronously from:

deferred_probe_work_func()
bus_probe_device()
device_initial_probe()
__device_attach()

So if the commit's intention was to check the "dead" flag in all
asynchronous code paths, then a check is also necessary in
__device_attach(). Add the missing check.

Fixes: 3451a495ef24 ("driver core: Establish order of operations for device_add and device_del via bitflag")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.1+
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Link: https://lore.kernel.org/r/de88a23a6fe0ef70f7cfd13c8aea9ab51b4edab6.1594214103.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/base/dd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -846,7 +846,9 @@ static int __device_attach(struct device
int ret = 0;

device_lock(dev);
- if (dev->driver) {
+ if (dev->p->dead) {
+ goto out_unlock;
+ } else if (dev->driver) {
if (device_is_bound(dev)) {
ret = 1;
goto out_unlock;