On Mon, Jul 04, 2022 at 05:05:11PM +0200, Marco Elver wrote:
> +static bool bp_constraints_is_locked(struct perf_event *bp)
> +{
> + struct mutex *tsk_mtx = get_task_bps_mutex(bp);
> +
> + return percpu_is_write_locked(&bp_cpuinfo_sem) ||
> + (tsk_mtx ? mutex_is_locked(tsk_mtx) :
> + percpu_is_read_locked(&bp_cpuinfo_sem));
> +}
> @@ -426,18 +521,28 @@ static int modify_bp_slot(struct perf_event *bp, u64
> old_type, u64 new_type)
> */
> int dbg_reserve_bp_slot(struct perf_event *bp)
> {
> - if (mutex_is_locked(&nr_bp_mutex))
> + int ret;
> +
> + if (bp_constraints_is_locked(bp))
> return -1;
>
> - return __reserve_bp_slot(bp, bp->attr.bp_type);
> + /* Locks aren't held; disable lockdep assert checking. */
> + lockdep_off();
> + ret = __reserve_bp_slot(bp, bp->attr.bp_type);
> + lockdep_on();
> +
> + return ret;
> }
>
> int dbg_release_bp_slot(struct perf_event *bp)
> {
> - if (mutex_is_locked(&nr_bp_mutex))
> + if (bp_constraints_is_locked(bp))
> return -1;
>
> + /* Locks aren't held; disable lockdep assert checking. */
> + lockdep_off();
> __release_bp_slot(bp, bp->attr.bp_type);
> + lockdep_on();
>
> return 0;
> }
Urggghhhh... this is horrible crap. That is, the current code is that
and this makes it worse :/
