In cpus_excl_conflict(), when a valid local partition A1 uses implicit
exclusive CPUs (cpuset.cpus set without cpuset.cpus.exclusive, so
sibling->exclusive_cpus is empty while sibling->effective_xcpus is
populated), a sibling cgroup B1 can still set cpuset.cpus.exclusive on
the same CPUs because cpus_excl_conflict() only checks
sibling->exclusive_cpus.
Fall back to sibling->effective_xcpus in cpus_excl_conflict() when
sibling->exclusive_cpus is empty, 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
tools/testing/selftests/cgroup/test_cpuset_prs.sh.
Fixes: 2a3602030d80 ("cgroup/cpuset: Don't invalidate sibling partitions on
cpuset.cpus conflict")
Cc: [email protected]
Assisted-by: LLM
Signed-off-by: Hui Peng <[email protected]>
---
Changes in v3:
- Split out from the validate_partition() fix into patch 3/3 and add the
Fixes tag for commit 2a3602030d80, as pointed out by Guopeng Zhang.
kernel/cgroup/cpuset.c | 5 ++++-
tools/testing/selftests/cgroup/test_cpuset_prs.sh | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 7c5b4a8f1f3a..f46a51f07938 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -713,7 +713,10 @@ static inline bool cpus_excl_conflict(struct cpuset
*trial, struct cpuset *sibli
return true;
/* Exclusive_cpus cannot intersect */
- return cpumask_intersects(trial->exclusive_cpus,
sibling->exclusive_cpus);
+ return cpumask_intersects(trial->exclusive_cpus,
+ cpumask_empty(sibling->exclusive_cpus)
+ ? sibling->effective_xcpus
+ : sibling->exclusive_cpus);
}
static inline bool mems_excl_conflict(struct cpuset *cs1, struct cpuset *cs2)
diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index f4d1822d4e21..f62155cf6162 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -445,6 +445,7 @@ TEST_MATRIX=(
# Changes to cpuset.cpus.exclusive that violate exclusivity rule is
rejected
" C0-3 . . C4-5 X0-3 . . X3-5 1
A1:0-3|B1:4-5"
+ " C0-3:P1 . . C4-5 . . . X3-5 1
A1:0-3|B1:4-5 A1:P1|B1:P0"
# cpuset.cpus.exclusive cannot be set to a superset of sibling's
cpuset.cpus
" C0-3 . . C4-5 X3-5 . . . 1
A1:0-3|B1:4-5"
--
2.49.0
