Re: [syzbot] [kernel?] possible deadlock in stack_depot_put

[Tetsuo Handa]

On 2023/12/05 20:31, Hillf Danton wrote:
> Unlike down_trylock(), mutex_trylock() is unable to trigger any lockdep
> warning, so why is a binary semaphore prefered over mutex?

The mutex has limitations which makes it impossible to use for console lock.

https://elixir.bootlin.com/linux/v6.7-rc4/source/kernel/locking/mutex.c#L537

By the way, this is a KASAN bug saying "refcount_t: underflow; use-after-free.".
Possibly a candidate for printk_deferred_enter() user?