6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
[ Upstream commit f5717c93a1b999970f3a64d771a1a9ee68cc37d0 ]
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 36454023f50b ("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: 36454023f50b ("sched_ext: Track tasks that are subjects of the in-flight SCX operation")
Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/sched/ext.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 45e7461fd4c94..b88fa640325e5 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3447,7 +3447,7 @@ 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)
@@ -3594,7 +3594,7 @@ 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);
}
@@ -3623,7 +3623,7 @@ 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);
}
--
2.39.5
