The following commit has been merged into the sched/core branch of tip:
Commit-ID: fdf756f7127185eeffe00e918e66dfee797f3625
Gitweb: https://git.kernel.org/tip/fdf756f7127185eeffe00e918e66dfee797f3625
Author: Peter Zijlstra <[email protected]>
AuthorDate: Fri, 30 Sep 2022 16:39:46 +02:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Fri, 30 Sep 2022 16:50:39 +02:00
sched: Fix more TASK_state comparisons
Boris reported hung_task splats after commit 5aec788aeb8e ("sched: Fix
TASK_state comparisons"). Upon closer consideration of that change it
doesn't only exclude TASK_KILLABLE, but also TASK_IDLE.
Update the comment to reflect this fact and add an additional
TASK_NOLOAD test to exclude them.
Additionally, remove the TASK_FREEZABLE early exit from
check_hung_task(), a freezable task is not a frozen task.
Fixes: 5aec788aeb8e ("sched: Fix TASK_state comparisons")
Reported-by: Borislav Petkov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Borislav Petkov <[email protected]>
---
kernel/hung_task.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 3a15169..c71889f 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -95,7 +95,7 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
* Ensure the task is not frozen.
* Also, skip vfork and any other user process that freezer should skip.
*/
- if (unlikely(READ_ONCE(t->__state) & (TASK_FREEZABLE | TASK_FROZEN)))
+ if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN))
return;
/*
@@ -200,10 +200,14 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
goto unlock;
last_break = jiffies;
}
- /* skip the TASK_KILLABLE tasks -- these can be killed */
+ /*
+ * skip the TASK_KILLABLE tasks -- these can be killed
+ * skip the TASK_IDLE tasks -- those are genuinely idle
+ */
state = READ_ONCE(t->__state);
if ((state & TASK_UNINTERRUPTIBLE) &&
- !(state & TASK_WAKEKILL))
+ !(state & TASK_WAKEKILL) &&
+ !(state & TASK_NOLOAD))
check_hung_task(t, timeout);
}
unlock: