On Thu, Jun 30, 2016 at 09:59:41AM +0800, Fam Zheng wrote:

Documentation/kobject.txt:

quoted

Use the KOBJ_ADD action for when the kobject is first added to the kernel.
This should be done only after any attributes or children of the kobject
have been initialized properly, as userspace will instantly start to look
for them when this call happens.

Unfortunately it seems impossible to fix this generally without touching the
offending callers.  The approach I'm proposing here is adding a flag to
suppress uevent in add_disk(), which is patch 1, then in later patches, convert
any caller to only trigger the uevent when attributes are added.

We (or rather Dan) is touching most add_disk callers anyway for the
driverfs_dev removal.  Let's just pass the array of attributes to
a disk_add variant and solve the issue for real.