On 01/28, Breno Leitao wrote:
>
> The list_for_each_entry_rcu() in filter_chain() uses
> rcu_read_lock_trace_held() as the lockdep condition, but the function
> holds consumer_rwsem, not the RCU trace lock.
>
> This gives me the following output when running with some locking debug
> option enabled:
>
> kernel/events/uprobes.c:1141 RCU-list traversed in non-reader section!!
> filter_chain
> register_for_each_vma
> uprobe_unregister_nosync
> __probe_event_disable
>
> Remove the incorrect lockdep condition since the rwsem provides
> sufficient protection for the list traversal.
I hope Andrii will recheck, but looks obviously correct to me.
> Fixes: 87195a1ee332a ("uprobes: switch to RCU Tasks Trace flavor for better
> performance")
This commit just change the __list_check_rcu() condition...
Perhaps
Fixes: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under
SRCU protection")
makes more sense?
Acked-by: Oleg Nesterov <[email protected]>
