5.10-stable patches

added patches:
	cgroup-move-rcu_head-up-near-the-top-of-cgroup_root.patch

diff --git a/queue-5.10/cgroup-move-rcu_head-up-near-the-top-of-cgroup_root.patch b/queue-5.10/cgroup-move-rcu_head-up-near-the-top-of-cgroup_root.patch
new file mode 100644 (file)
index 0000000..5552016
--- /dev/null
+++ b/queue-5.10/cgroup-move-rcu_head-up-near-the-top-of-cgroup_root.patch
@@ -0,0 +1,66 @@
+From a7fb0423c201ba12815877a0b5a68a6a1710b23a Mon Sep 17 00:00:00 2001
+From: Waiman Long <longman@redhat.com>
+Date: Thu, 7 Dec 2023 08:46:14 -0500
+Subject: cgroup: Move rcu_head up near the top of cgroup_root
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Waiman Long <longman@redhat.com>
+
+commit a7fb0423c201ba12815877a0b5a68a6a1710b23a upstream.
+
+Commit d23b5c577715 ("cgroup: Make operations on the cgroup root_list RCU
+safe") adds a new rcu_head to the cgroup_root structure and kvfree_rcu()
+for freeing the cgroup_root.
+
+The current implementation of kvfree_rcu(), however, has the limitation
+that the offset of the rcu_head structure within the larger data
+structure must be less than 4096 or the compilation will fail. See the
+macro definition of __is_kvfree_rcu_offset() in include/linux/rcupdate.h
+for more information.
+
+By putting rcu_head below the large cgroup structure, any change to the
+cgroup structure that makes it larger run the risk of causing build
+failure under certain configurations. Commit 77070eeb8821 ("cgroup:
+Avoid false cacheline sharing of read mostly rstat_cpu") happens to be
+the last straw that breaks it. Fix this problem by moving the rcu_head
+structure up before the cgroup structure.
+
+Fixes: d23b5c577715 ("cgroup: Make operations on the cgroup root_list RCU safe")
+Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
+Closes: https://lore.kernel.org/lkml/20231207143806.114e0a74@canb.auug.org.au/
+Signed-off-by: Waiman Long <longman@redhat.com>
+Acked-by: Yafang Shao <laoar.shao@gmail.com>
+Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
+Reviewed-by: Michal Koutný <mkoutny@suse.com>
+Signed-off-by: Tejun Heo <tj@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/cgroup-defs.h |    8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/include/linux/cgroup-defs.h
++++ b/include/linux/cgroup-defs.h
+@@ -501,6 +501,10 @@ struct cgroup_root {
+       /* Unique id for this hierarchy. */
+       int hierarchy_id;
+ 
++      /* A list running through the active hierarchies */
++      struct list_head root_list;
++      struct rcu_head rcu;    /* Must be near the top */
++
+       /* The root cgroup.  Root is destroyed on its release. */
+       struct cgroup cgrp;
+ 
+@@ -510,10 +514,6 @@ struct cgroup_root {
+       /* Number of cgroups in the hierarchy, used only for /proc/cgroups */
+       atomic_t nr_cgrps;
+ 
+-      /* A list running through the active hierarchies */
+-      struct list_head root_list;
+-      struct rcu_head rcu;
+-
+       /* Hierarchy-specific flags */
+       unsigned int flags;
+ 

diff --git a/queue-5.10/series b/queue-5.10/series
index c7f3ff8f7525d51cd2195e9f254a6d80fc23fef7..55f992eb196c5ec73ad101fb71d87743ca8535fa 100644 (file)
--- a/queue-5.10/series
+++ b/queue-5.10/series
@@ -52,3 +52,4 @@ inet-inet_defrag-prevent-sk-release-while-still-in-use.patch
 x86-ibt-ftrace-search-for-__fentry__-location.patch
 ftrace-fix-possible-use-after-free-issue-in-ftrace_location.patch
 gpiolib-cdev-ignore-reconfiguration-without-direction.patch
+cgroup-move-rcu_head-up-near-the-top-of-cgroup_root.patch