Re: [PATCH 1/2] hung_task: Show the blocker task if the task is hung on mutex

[Steven Rostedt]

On Wed, 19 Feb 2025 20:36:13 -0500
Waiman Long <llong@xxxxxxxxxx> wrote:

 
> >>>> this field, we don't need to take lock, though taking the wait_lock may
> >>>> still be needed to examine other information inside the mutex.  
> > Do we need to take it just for accessing owner, which is in an atomic?  
> 
> Right. I forgot it is an atomic_long_t. In that case, no lock should be 
> needed.

Now if we have a two fields to read:

	block_flags (for the type of lock) and blocked_on (for the lock)

We need a way to synchronize the two. What happens if we read the type, and
the task wakes up and and then blocks on a different type of lock?

Then the lock read from blocked_on could be a different type of lock than
what is expected.

-- Steve