softlockup: convert read_lock in hung_task to rcu_read_lock
softlockup: convert read_lock in hung_task to rcu_read_lock

Since the tasklist is protected by rcu list operations, it is safe
to convert the read_lock()s to rcu_read_lock().

Suggested-by: Peter Zijlstra <645ca7d3a8d3d4f60557176cd361ea8351edc32b@chello.nl>
Signed-off-by: Mandeep Singh Baines <19acf4ef1f391f4aab404dc5703cac3632e06f3a@google.com>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas