Hui Peng 31c88350b7 cgroup/cpuset: Return PERR_NOCPUS in remote_partition_enable() on subpartitions_cpus conflict ... When a remote partition is created underneath an existing local partition via a non-partition (PRS_MEMBER) intermediate cgroup, update_prstate() sees parent->partition_root_state == PRS_MEMBER and calls remote_partition_enable(). Commit 86888c7bd1 ("cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs") replaced the cpumask_intersects(tmp->new_cpus, subpartitions_cpus) error check in remote_partition_enable() with WARN_ON_ONCE(). As a result, remote_partition_enable() emits a warning and proceeds to enable the remote partition on CPUs that are already owned by the ancestor local partition in subpartitions_cpus. This can be reproduced on Linux 7.3.0-rc3 with: mkdir -p /tmp/cg1 mount -t cgroup2 none /tmp/cg1 echo "+cpuset" > /tmp/cg1/cgroup.subtree_control mkdir /tmp/cg1/A echo 1 > /tmp/cg1/A/cpuset.cpus echo 1 > /tmp/cg1/A/cpuset.cpus.exclusive echo root > /tmp/cg1/A/cpuset.cpus.partition echo "+cpuset" > /tmp/cg1/A/cgroup.subtree_control mkdir /tmp/cg1/A/B echo 1 > /tmp/cg1/A/B/cpuset.cpus echo 1 > /tmp/cg1/A/B/cpuset.cpus.exclusive echo "+cpuset" > /tmp/cg1/A/B/cgroup.subtree_control mkdir /tmp/cg1/A/B/D echo 1 > /tmp/cg1/A/B/D/cpuset.cpus echo 1 > /tmp/cg1/A/B/D/cpuset.cpus.exclusive echo root > /tmp/cg1/A/B/D/cpuset.cpus.partition which triggers: WARNING: kernel/cgroup/cpuset.c:1594 at remote_partition_enable+0x1c1/0x300 and leaves both /tmp/cg1/A and /tmp/cg1/A/B/D as active root partitions claiming exclusive CPU 1. Fix this by returning PERR_NOCPUS when tmp->new_cpus intersects subpartitions_cpus in remote_partition_enable(), matching the error code used by remote_cpus_update() for the same subpartitions_cpus conflict, and add a regression test case to tools/testing/selftests/cgroup/test_cpuset_prs.sh. Tested in QEMU on Linux 7.3.0-rc3 using the reproducer above and tools/testing/selftests/cgroup/test_cpuset_prs.sh. Fixes: 86888c7bd1 ("cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs") Suggested-by: Guopeng Zhang <guopeng.zhang@linux.dev> Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Hui Peng <benquike@gmail.com> Reviewed-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>		2026-09-26 08:07:26 -10:00
..
accounting	tools/accounting/getdelays: fix -Wformat-truncation warning in format_timespec	2026-05-28 21:24:40 -07:00
arch	perf tools changes for v7.2:	2026-06-23 11:34:49 -07:00
bootconfig	Bootconfig updates for v7.2	2026-06-16 17:29:24 +05:30
bpf	tools/bpf: build: Append extra cflags	2026-06-14 17:32:53 -07:00
build	perf tools changes for v7.2:	2026-06-23 11:34:49 -07:00
certs
cgroup	tools/cgroup: iocost_monitor: parse help before importing drgn	2026-06-24 08:59:01 -10:00
counter
crypto
debugging
dma
docs
firewire
firmware
gpio
hv
iio	iio: core: Add IIO_COVERAGE channel type	2026-05-31 11:01:50 +01:00
include	bpf-next-7.2	2026-06-17 09:18:14 +01:00
kvm/kvm_stat
laptop
leds
lib	perf tools changes for v7.2:	2026-06-23 11:34:49 -07:00
memory-model
mm	slab changes for 7.2 - part 2	2026-06-22 08:28:48 -07:00
net	tools: ynl: try to avoid the very slow YAML loader	2026-06-04 15:36:12 -07:00
objtool
pcmcia
perf	perf tools changes for v7.2:	2026-06-23 11:34:49 -07:00
power	platform-drivers-x86 for v7.2-1	2026-06-23 08:31:33 -07:00
rcu
sched
sched_ext	sched_ext: Move sources under kernel/sched/ext/	2026-06-22 05:32:56 -10:00
scripts
sound
spi
testing	cgroup/cpuset: Return PERR_NOCPUS in remote_partition_enable() on subpartitions_cpus conflict	2026-09-26 08:07:26 -10:00
thermal
time
tracing	rtla: Fix parsing of multi-character short options	2026-06-04 10:53:25 +02:00
unittests
usb
verification	verification/rvgen: Fix ltl2k writing True as a literal	2026-06-04 16:44:25 +02:00
virtio	tools/virtio: fix build for kmalloc_obj API and missing stubs	2026-06-10 02:16:59 -04:00
wmi
workqueue
writeback
Makefile