On Tue, Jan 31, 2023 at 10:48:03AM -0500, Waiman Long wrote: > 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") > Reported-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxx> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Applied to cgroup/for-6.2-fixes w/ stable cc added. Thanks. -- tejun
