On Wed, Dec 5, 2018 at 9:25 AM Alexander Duyck
Add an additional bit flag to the device struct named "dead".
This additional flag provides a guarantee that when a device_del is
executed on a given interface an async worker will not attempt to attach
the driver following the earlier device_del call. Previously this
guarantee was not present and could result in the device_del call
attempting to remove a driver from an interface only to have the async
worker attempt to probe the driver later when it finally completes the
asynchronous probe call.
Signed-off-by: Alexander Duyck <alexander.h.duyck(a)linux.intel.com>
drivers/base/core.c | 11 +++++++++++
drivers/base/dd.c | 8 ++++++--
include/linux/device.h | 5 +++++
3 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index f3e6ca4170b4..70358327303b 100644
@@ -2075,6 +2075,17 @@ void device_del(struct device *dev)
struct kobject *glue_dir = NULL;
struct class_interface *class_intf;
+ * Hold the device lock and set the "dead" flag to guarantee that
+ * the update behavior is consistent with the other bitfields near
+ * it and that we cannot have an asynchronous probe routine trying
+ * to run while we are tearing out the bus/class/sysfs from
+ * underneath the device.
+ dev->dead = true;
/* Notify clients of device removal. This call must come
* before dpm_sysfs_remove().
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 88713f182086..3bb8c3e0f3da 100644
@@ -774,6 +774,10 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t
+ /* device is or has been removed from the bus, just bail out */
+ if (dev->dead)
+ goto out_unlock;
What do you think about moving this check into
__device_attach_driver() alongside all the other checks? That way we
also get ->dead checking through the __device_attach() path.
...and after that maybe it could be made a common helper
(dev_driver_checks()?) shared between __device_attach_driver() and
__driver_attach() to reduce some duplication.