mutex:move mutex holder to struct mutex_s.

[XinStellaris]

Signed-off-by: 田昕 tianxin7@xiaomi.com

Summary

We move the mutex holder to struct mutex_s so that we can trace who holds the mutex when deadlock happens.
We also print possible mutex holder in sched_dumpstack.

Impact

mutex_t and related code.

Testing

Tested on ESP32C3

[XinStellaris]

@xiaoxiang781216 @liguiding please review

[XinStellaris]

I am not sure whether we should print mutex holder in sched_dumpstack.
It may be helpful when we lack coredump or gdb.

[GUIDINGLI]

I am not sure whether we should print mutex holder in sched_dumpstack. It may be helpful when we lack coredump or gdb.

In a real device and there is no JTAG (mainly for the device just sold out), this method will be helpful for debugging

[pkarashchenko]

This change reminded me #6376 (comment) discussion.

[xiaoxiang781216]

why not move to ps and crash dump?

[XinStellaris]

cmd_ps seems a good place to go.
What do you mean by crash dump? board_crashdump?

[xiaoxiang781216]

e.g. arm_dumpstate

[xiaoxiang781216]

not all semaphore have holder field.

[XinStellaris]

As a matter of fact, I don't know how to tell the difference.
There is no way to differentiate waiting on a sem or on a mutex.
So I just print possible mutex holder anyway.

What's your suggestion?

[pkarashchenko]

let's check the wait object. If semaphore has PRIOINHERIT_FLAGS_ENABLE flag then most probably it is a mutex and we can upcast it to mutex_t. That is one of the possible variants

[xiaoxiang781216]

But it can't handle the project which doesn't enable priority inheritance.

[XinStellaris]

how about we design an internal function like:
int _nxsem_wait(FAR sem_t *sem, bool is_mutex)

Then we can differentiate mutex and sem.
After that, we can add a new TSTATE_WAIT_MUTEX, then we know if a task is waiting on mutex, and we can print the mutex holder in such case.

[xiaoxiang781216]

An other approach could add a new flag in sem_t::flags to indicate whether is mutex or sem

[pkarashchenko]

IMO we need to design and implement a separate kernel object and cleanup priority inheritance from semaphore

[XinStellaris]

@anjiahao1 please review this