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

[Waiman Long <llong@redhat.com>]

On 2/19/25 9:45 PM, Sergey Senozhatsky wrote:
> On (25/02/20 08:09), Masami Hiramatsu wrote:
>> So something like this?
>>
>> unsigned int	block_flags;
>> union {
>> 	struct mutex	*mutex;
>> 	struct rwsem	+rwsem;
>> 	struct rtmutex	*rtmutex;
>> } blocked_on;
>>
>> enum {
>> 	BLOCKED_ON_MUTEX;
>> 	BLOCKED_ON_RWSEM;
>> 	BLOCKED_ON_RTMUTEX;
>> 	BLOCKED_ON_IO;
>> } block_reason;
> I totally like this and always wanted to have something simlar,
> something for all "sleepable" synchronization primitives, lightweight
> enough (memory and CPU usage wise) to run on consumer devices.  I was
> thinking of a rhashtable where each entry represents "sleepable"
> primitive with a "owner" pointer and a list of "blocked on" tasks.
> But I'm sure you'll have a better idea.
>
> If I may add a couple of "wishes", can we also add:
> - completions (so that things like wait_for_completion and
>    synchronize srcu get covered)
> - wait on bit (so that things like lock_buffer and so on get covered)

Bit lock doesn't have a owner field to track the owning task.

Cheers,
Longman

>