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mirror of synced 2025-03-06 20:59:54 +01:00

sched_ext: Use SCX_CALL_OP_TASK in task_tick_scx

Now when we use scx_bpf_task_cgroup() in ops.tick() to get the cgroup of
the current task, the following error will occur:

scx_foo[3795244] triggered exit kind 1024:
  runtime error (called on a task not being operated on)

The reason is that we are using SCX_CALL_OP() instead of SCX_CALL_OP_TASK()
when calling ops.tick(), which triggers the error during the subsequent
scx_kf_allowed_on_arg_tasks() check.

SCX_CALL_OP_TASK() was first introduced in commit 36454023f5 ("sched_ext:
Track tasks that are subjects of the in-flight SCX operation") to ensure
task's rq lock is held when accessing task's sched_group. Since ops.tick()
is marked as SCX_KF_TERMINAL and task_tick_scx() is protected by the rq
lock, we can use SCX_CALL_OP_TASK() to avoid the above issue. Similarly,
the same changes should be made for ops.disable() and ops.exit_task(), as
they are also protected by task_rq_lock() and it's safe to access the
task's task_group.

Fixes: 36454023f5 ("sched_ext: Track tasks that are subjects of the in-flight SCX operation")
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Chuyi Zhou 2025-02-12 21:09:35 +08:00 committed by Tejun Heo
parent 2e2006c91c
commit f5717c93a1

View file

@ -3899,7 +3899,7 @@ static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued)
curr->scx.slice = 0;
touch_core_sched(rq, curr);
} else if (SCX_HAS_OP(tick)) {
SCX_CALL_OP(SCX_KF_REST, tick, curr);
SCX_CALL_OP_TASK(SCX_KF_REST, tick, curr);
}
if (!curr->scx.slice)
@ -4046,7 +4046,7 @@ static void scx_ops_disable_task(struct task_struct *p)
WARN_ON_ONCE(scx_get_task_state(p) != SCX_TASK_ENABLED);
if (SCX_HAS_OP(disable))
SCX_CALL_OP(SCX_KF_REST, disable, p);
SCX_CALL_OP_TASK(SCX_KF_REST, disable, p);
scx_set_task_state(p, SCX_TASK_READY);
}
@ -4075,7 +4075,7 @@ static void scx_ops_exit_task(struct task_struct *p)
}
if (SCX_HAS_OP(exit_task))
SCX_CALL_OP(SCX_KF_REST, exit_task, p, &args);
SCX_CALL_OP_TASK(SCX_KF_REST, exit_task, p, &args);
scx_set_task_state(p, SCX_TASK_NONE);
}