diff options
| author | Waiman Long <longman@redhat.com> | 2023-01-31 10:48:03 -0500 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2023-01-31 12:14:02 -1000 |
| commit | e5ae8803847b80fe9d744a3174abe2b7bfed222a (patch) | |
| tree | d5bdf23c5bba0d92306483780f75f0f2eb2d153b | |
| parent | 58706f7fb045b7019bada81fa17f372189315fe5 (diff) | |
| download | linux-e5ae8803847b80fe9d744a3174abe2b7bfed222a.tar.gz | |
cgroup/cpuset: Fix wrong check in update_parent_subparts_cpumask()
It was found that the check to see if a partition could use up all
the cpus from the parent cpuset in update_parent_subparts_cpumask()
was incorrect. As a result, it is possible to leave parent with no
effective cpu left even if there are tasks in the parent cpuset. This
can lead to system panic as reported in [1].
Fix this probem by updating the check to fail the enabling the partition
if parent's effective_cpus is a subset of the child's cpus_allowed.
Also record the error code when an error happens in update_prstate()
and add a test case where parent partition and child have the same cpu
list and parent has task. Enabling partition in the child will fail in
this case.
[1] https://www.spinics.net/lists/cgroups/msg36254.html
Fixes: f0af1bfc27b5 ("cgroup/cpuset: Relax constraints to partition & cpus changes")
Cc: stable@vger.kernel.org # v6.1
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/cgroup/cpuset.c | 3 | ||||
| -rwxr-xr-x | tools/testing/selftests/cgroup/test_cpuset_prs.sh | 1 |
2 files changed, 3 insertions, 1 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index a29c0b13706bb0..205dc9edcaa965 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1346,7 +1346,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd, * A parent can be left with no CPU as long as there is no * task directly associated with the parent partition. */ - if (!cpumask_intersects(cs->cpus_allowed, parent->effective_cpus) && + if (cpumask_subset(parent->effective_cpus, cs->cpus_allowed) && partition_is_populated(parent, cs)) return PERR_NOCPUS; @@ -2324,6 +2324,7 @@ out: new_prs = -new_prs; spin_lock_irq(&callback_lock); cs->partition_root_state = new_prs; + WRITE_ONCE(cs->prs_err, err); spin_unlock_irq(&callback_lock); /* * Update child cpusets, if present. diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh index 186e1c26867ef5..75c100de90ffe2 100755 --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh @@ -268,6 +268,7 @@ TEST_MATRIX=( # Taking away all CPUs from parent or itself if there are tasks # will make the partition invalid. " S+ C2-3:P1:S+ C3:P1 . . T C2-3 . . 0 A1:2-3,A2:2-3 A1:P1,A2:P-1" + " S+ C3:P1:S+ C3 . . T P1 . . 0 A1:3,A2:3 A1:P1,A2:P-1" " S+ $SETUP_A123_PARTITIONS . T:C2-3 . . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1" " S+ $SETUP_A123_PARTITIONS . T:C2-3:C1-3 . . . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" |