On 2024-04-04 12:25:36 [+0200], To dri-devel@xxxxxxxxxxxxxxxxxxxxx wrote:
> PREEMPT_RT has a different locking implementation for ww_mutex. The
> base mutex of struct ww_mutex is declared as struct WW_MUTEX_BASE. The
> latter is defined as `mutex' for non-PREEMPT_RT builds and `rt_mutex'
> for PREEMPT_RT builds.
>
> Using mutex_lock() directly on the base mutex in
> ttm_bo_reserve_deadlock() leads to compile error on PREEMPT_RT.
>
> The locking-selftest has its own defines to deal with this and it is
> probably best to defines the needed one within the test program since
> their usefulness is limited outside of well known selftests.
>
> Provide ww_mutex_base_lock() which points to the correct function for
> PREEMPT_RT and non-PREEMPT_RT builds.
>
> Fixes: 995279d280d1e ("drm/ttm/tests: Add tests for ttm_bo functions")
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>
> For the record, testing led to
> | WARNING: CPU: 5 PID: 2089 at include/drm/ttm/ttm_bo.h:247 ttm_bo_reserve_no_wait_ticket+0xe8/0x150 [ttm_bo_test]
>
> but this occurred with and without RT on v6.9-rc2.
a friendly ping.
Sebastian
