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linux-stable-mirror/kernel
Chuyi Zhou 9a0a411f59 sched_ext: Use SCX_CALL_OP_TASK in task_tick_scx
[ Upstream commit f5717c93a1 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21 14:01:21 +01:00
..
2024-10-09 12:47:19 -07:00
2025-02-08 09:57:35 +01:00
2024-09-27 08:18:43 -07:00