Commit d94d09a2 authored by Tejun Heo's avatar Tejun Heo
Browse files

sched_ext: When calling ops.dispatch() @prev must be on the same scx_sched 



The @prev parameter passed into ops.dispatch() is expected to be on the
same sched. Passing in @prev which isn't on the sched can spuriously
trigger failures that can kill the scheduler. Pass in @prev iff it's on
the same sched.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarAndrea Righi <arighi@nvidia.com>
parent 39d0b2c4

kernel/sched/ext.c

+3 −2
Original line number Diff line number Diff line
@@ -2392,9 +2392,10 @@ static bool scx_dispatch_sched(struct scx_sched *sch, struct rq *rq, 
			       struct task_struct *prev)

{

	struct scx_dsp_ctx *dspc = this_cpu_ptr(scx_dsp_ctx);

	bool prev_on_scx = prev->sched_class == &ext_sched_class;

	int nr_loops = SCX_DSP_MAX_LOOPS;

	s32 cpu = cpu_of(rq);

	bool prev_on_sch = (prev->sched_class == &ext_sched_class) &&

		scx_task_on_sched(sch, prev);



	if (consume_global_dsq(sch, rq))

		return true;
@@ -2418,7 +2419,7 @@ static bool scx_dispatch_sched(struct scx_sched *sch, struct rq *rq, 
		dspc->nr_tasks = 0;



		SCX_CALL_OP(sch, SCX_KF_DISPATCH, dispatch, rq, cpu,

			    prev_on_scx ? prev : NULL);

			    prev_on_sch ? prev : NULL);



		flush_dispatch_buf(sch, rq);