| Message ID | 20230317151508.1225282-2-longman@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 292fd843de26c551856e66faf134512c52dd78b4 |
| Headers | show |
| Series | cgroup/cpuset: Miscellaneous updates | expand |
On Fri, Mar 17, 2023 at 11:15:05AM -0400, Waiman Long wrote: > It was found that commit 7a2127e66a00 ("cpuset: Call > set_cpus_allowed_ptr() with appropriate mask for task") introduced a bug > that corrupted "cpuset.cpus" of a partition root when it was updated. > > It is because the tmp->new_cpus field of the passed tmp parameter > of update_parent_subparts_cpumask() should not be used at all as > it contains important cpumask data that should not be overwritten. > Fix it by using tmp->addmask instead. > > Also update update_cpumask() to make sure that trialcs->cpu_allowed > will not be corrupted until it is no longer needed. > > Fixes: 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") > Signed-off-by: Waiman Long <longman@redhat.com> Applied to cgroup/for-6.3-fixes w/ stable cc'd. Thanks.
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 636f1c682ac0..f310915d1257 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1513,7 +1513,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd, spin_unlock_irq(&callback_lock); if (adding || deleting) - update_tasks_cpumask(parent, tmp->new_cpus); + update_tasks_cpumask(parent, tmp->addmask); /* * Set or clear CS_SCHED_LOAD_BALANCE when partcmd_update, if necessary. @@ -1770,10 +1770,13 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, /* * Use the cpumasks in trialcs for tmpmasks when they are pointers * to allocated cpumasks. + * + * Note that update_parent_subparts_cpumask() uses only addmask & + * delmask, but not new_cpus. */ tmp.addmask = trialcs->subparts_cpus; tmp.delmask = trialcs->effective_cpus; - tmp.new_cpus = trialcs->cpus_allowed; + tmp.new_cpus = NULL; #endif retval = validate_change(cs, trialcs); @@ -1838,6 +1841,11 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, } spin_unlock_irq(&callback_lock); +#ifdef CONFIG_CPUMASK_OFFSTACK + /* Now trialcs->cpus_allowed is available */ + tmp.new_cpus = trialcs->cpus_allowed; +#endif + /* effective_cpus will be updated here */ update_cpumasks_hier(cs, &tmp, false);
It was found that commit 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") introduced a bug that corrupted "cpuset.cpus" of a partition root when it was updated. It is because the tmp->new_cpus field of the passed tmp parameter of update_parent_subparts_cpumask() should not be used at all as it contains important cpumask data that should not be overwritten. Fix it by using tmp->addmask instead. Also update update_cpumask() to make sure that trialcs->cpu_allowed will not be corrupted until it is no longer needed. Fixes: 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") Signed-off-by: Waiman Long <longman@redhat.com> --- kernel/cgroup/cpuset.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)