Mel Gorman 748d2e9585 sched/core: Do not requeue task on CPU excluded from cpus_mask ... [ Upstream commit 751d4cbc43 ] The following warning was triggered on a large machine early in boot on a distribution kernel but the same problem should also affect mainline. WARNING: CPU: 439 PID: 10 at ../kernel/workqueue.c:2231 process_one_work+0x4d/0x440 Call Trace: <TASK> rescuer_thread+0x1f6/0x360 kthread+0x156/0x180 ret_from_fork+0x22/0x30 </TASK> Commit c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu") optimises ttwu by queueing a task that is descheduling on the wakelist, but does not check if the task descheduling is still allowed to run on that CPU. In this warning, the problematic task is a workqueue rescue thread which checks if the rescue is for a per-cpu workqueue and running on the wrong CPU. While this is early in boot and it should be possible to create workers, the rescue thread may still used if the MAYDAY_INITIAL_TIMEOUT is reached or MAYDAY_INTERVAL and on a sufficiently large machine, the rescue thread is being used frequently. Tracing confirmed that the task should have migrated properly using the stopper thread to handle the migration. However, a parallel wakeup from udev running on another CPU that does not share CPU cache observes p->on_cpu and uses task_cpu(p), queues the task on the old CPU and triggers the warning. Check that the wakee task that is descheduling is still allowed to run on its current CPU and if not, wait for the descheduling to complete and select an allowed CPU. Fixes: c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20220804092119.20137-1-mgorman@techsingularity.net Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-08-17 14:24:15 +02:00
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autogroup.c	sched/fair: Prevent dead task groups from regaining cfs_rq's	2021-11-25 09:48:32 +01:00
autogroup.h
clock.c
completion.c
core.c	sched/core: Do not requeue task on CPU excluded from cpus_mask	2022-08-17 14:24:15 +02:00
core_sched.c
cpuacct.c	sched/cpuacct: Fix charge percpu cpuusage	2022-04-08 14:23:11 +02:00
cpudeadline.c
cpudeadline.h
cpufreq.c
cpufreq_schedutil.c	sched/uclamp: Fix iowait boost escaping uclamp restriction	2022-04-08 14:23:10 +02:00
cpupri.c
cpupri.h
cputime.c	cputime, cpuacct: Include guest time in user time in cpuacct.stat	2022-01-27 11:05:09 +01:00
deadline.c	sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()	2022-08-17 14:24:14 +02:00
debug.c	sched/debug: Remove mpol_get/put and task_lock/unlock from sched_show_numa	2022-04-08 14:23:10 +02:00
fair.c	sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg	2022-08-17 14:23:00 +02:00
features.h	sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg	2022-08-17 14:23:00 +02:00
idle.c	sched/idle: Make the idle timer expire in hard interrupt context	2021-09-09 10:36:16 +02:00
isolation.c
loadavg.c
Makefile
membarrier.c	sched/membarrier: Fix membarrier-rseq fence command missing from query bitmask	2022-02-01 17:27:05 +01:00
pelt.c
pelt.h	sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq	2022-06-09 10:22:48 +02:00
psi.c	sched/psi: report zeroes for CPU full at the system level	2022-06-09 10:22:48 +02:00
rt.c	nohz/full, sched/rt: Fix missed tick-reenabling bug in dequeue_task_rt()	2022-08-17 14:23:14 +02:00
sched-pelt.h
sched.h	sched: Remove the limitation of WF_ON_CPU on wakelist if wakee cpu is idle	2022-08-17 14:24:15 +02:00
smp.h
stats.c
stats.h	psi: Fix PSI_MEM_FULL state when tasks are in memstall and doing reclaim	2022-01-27 11:04:27 +01:00
stop_task.c
swait.c
topology.c
wait.c	wait: add wake_up_pollfree()	2021-12-14 10:57:15 +01:00
wait_bit.c