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    Subject[PATCH 4.19 32/92] driver core: Avoid binding drivers to dead devices
    Date
    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
    @@ -792,7 +792,9 @@ 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;

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