From 113330577851e0350db71e2fddd8068fcf543509 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Apr 20 2023 11:01:00 +0000
Subject: cgroup/cpuset: Fix partition root's cpuset.cpus update bug

(bsc#1012628).

---

diff --git a/patches.kernel.org/6.2.12-116-cgroup-cpuset-Fix-partition-root-s-cpuset.cpus.patch b/patches.kernel.org/6.2.12-116-cgroup-cpuset-Fix-partition-root-s-cpuset.cpus.patch
new file mode 100644
index 0000000..5ee1a4a
--- /dev/null
+++ b/patches.kernel.org/6.2.12-116-cgroup-cpuset-Fix-partition-root-s-cpuset.cpus.patch
@@ -0,0 +1,74 @@
+From: Waiman Long <longman@redhat.com>
+Date: Fri, 17 Mar 2023 11:15:05 -0400
+Subject: [PATCH] cgroup/cpuset: Fix partition root's cpuset.cpus update bug
+References: bsc#1012628
+Patch-mainline: 6.2.12
+Git-commit: 292fd843de26c551856e66faf134512c52dd78b4
+
+commit 292fd843de26c551856e66faf134512c52dd78b4 upstream.
+
+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>
+Cc: stable@vger.kernel.org # v6.2+
+Signed-off-by: Tejun Heo <tj@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Jiri Slaby <jslaby@suse.cz>
+---
+ kernel/cgroup/cpuset.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
+index ca826bd1..56fb79a4 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);
+ 
+-- 
+2.35.3
+
diff --git a/series.conf b/series.conf
index 49d0f02..c9e11ad 100644
--- a/series.conf
+++ b/series.conf
@@ -2343,6 +2343,7 @@
 	patches.kernel.org/6.2.12-113-PCI-MSI-Provide-missing-stub-for-pci_msix_can_.patch
 	patches.kernel.org/6.2.12-114-x86-PCI-Add-quirk-for-AMD-XHCI-controller-that.patch
 	patches.kernel.org/6.2.12-115-cgroup-fix-display-of-forceidle-time-at-root.patch
+	patches.kernel.org/6.2.12-116-cgroup-cpuset-Fix-partition-root-s-cpuset.cpus.patch
 
 	########################################################
 	# Build fixes that apply to the vanilla kernel too.