Re: [PATCH] mm: Replace verify_mm_writelocked() by lockdep_assert_held_exclusive()

Vlastimil Babka
2018-12-13T19:43:45Z

On 12/13/18 8:38 PM, Waiman Long wrote:
> Using down_read_trylock() to check if a task holds a write lock on
> a rwsem is not reliable. A task can hold a read lock on a rwsem and
> down_read_trylock() can fail if a writer is waiting in the wait queue.
>
> So use lockdep_assert_held_exclusive() instead which can do the right
> check when CONFIG_LOCKDEP is on.
>
> Signed-off-by: Waiman Long <longman@redhat.com>

There's already a patch in mmotm removing this completely:
https://www.ozlabs.org/~akpm/mmots/broken-out/mm-mmap-remove-verify_mm_writelocked.patch

Vlastimil