Linus Lüssing wrote:
sysfs_del_hardif invokes kobject_put, which might
sleep. However, we
are not allowed to sleep during a call_rcu. There is also no need to
do the removal with an atomic call_rcu, as kobject_put only frees the
kobject when there is no more reference to it anyway.
This commit basically revokes 7f32f2e8d97150ba5b80410dda86b01b0879fe8d,
despite not reintroducing the synchronize_rcu, our rcu_barrier should
This is an extreme bad idea as we would free the object before the rcu grace
period is over. This would mean that any parallel run through the list would
probably access memory which is invalid. So this is a good way to crash your
What makes you think that kobject_put sleeps? There is no code which proves
it. The only reason would be that kobject_put -> kobject_release ->
kobject_cleanup -> ... sleeps. Please complete that chain to show were the
problem is. If it really sleeps then please only do the kobject related
cleanup outside of call_rcu.