diff options
| author | Guanyou.Chen <chenguanyou9338@gmail.com> | 2026-05-22 21:09:59 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-06-02 12:26:10 +0200 |
| commit | 63c1a12bc0e09af7dee919c4fb4a300a719d5125 (patch) | |
| tree | 96daaa73475f4cb2492ee902aef498ae4ba43dec /kernel | |
| parent | 85358f0c6d590318539e657b0b3090871211193f (diff) | |
sched: restore timer_slack_ns when resetting RT policy on fork
Commit ed4fb6d7ef68 ("hrtimer: Use and report correct timerslack values
for realtime tasks") sets timer_slack_ns to 0 for RT tasks in
__setscheduler_params(). However, when an RT task with SCHED_RESET_ON_FORK
creates child threads, the children inherit timer_slack_ns=0 from the
parent. sched_fork() resets the child's policy to SCHED_NORMAL but does
not restore timer_slack_ns, leaving the child permanently running with
zero slack.
Fix this by restoring timer_slack_ns from default_timer_slack_ns in
sched_fork() when resetting from RT/DL to NORMAL policy, matching the
existing behavior in __setscheduler_params().
Note: this fix alone requires a correct default_timer_slack_ns to be
effective. See the following patch for that fix.
Fixes: ed4fb6d7ef68 ("hrtimer: Use and report correct timerslack values for realtime tasks")
Reported-by: Qiaoting.Lin <linqiaoting@xiaomi.com>
Signed-off-by: Guanyou.Chen <chenguanyou@xiaomi.com>
Signed-off-by: Chunhui.Li <chunhui.li@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260522131000.1664983-2-chenguanyou@xiaomi.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5a317f62a516..2cfe8932d5db 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4826,6 +4826,7 @@ int sched_fork(u64 clone_flags, struct task_struct *p) p->policy = SCHED_NORMAL; p->static_prio = NICE_TO_PRIO(0); p->rt_priority = 0; + p->timer_slack_ns = p->default_timer_slack_ns; } else if (PRIO_TO_NICE(p->static_prio) < 0) p->static_prio = NICE_TO_PRIO(0); |