From fdf756f7127185eeffe00e918e66dfee797f3625 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 30 Sep 2022 16:39:46 +0200 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Tested-by: Borislav Petkov --- kernel/hung_task.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel/hung_task.c') diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 3a15169ba2f8..c71889f3f3fc 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: -- cgit v1.2.3