This is a note to let you know that I've just added the patch titled
mm: kfence: fix using kfence_metadata without initialization in show_object()
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-kfence-fix-using-kfence_metadata-without-initialization-in-show_object.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1c86a188e03156223a34d09ce290b49bd4dd0403 Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Date: Wed, 15 Mar 2023 11:44:41 +0800
Subject: mm: kfence: fix using kfence_metadata without initialization in show_object()
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
commit 1c86a188e03156223a34d09ce290b49bd4dd0403 upstream.
The variable kfence_metadata is initialized in kfence_init_pool(), then,
it is not initialized if kfence is disabled after booting. In this case,
kfence_metadata will be used (e.g. ->lock and ->state fields) without
initialization when reading /sys/kernel/debug/kfence/objects. There will
be a warning if you enable CONFIG_DEBUG_SPINLOCK. Fix it by creating
debugfs files when necessary.
Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@xxxxxxxxxxxxx
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Tested-by: Marco Elver <elver@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: SeongJae Park <sjpark@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/kfence/core.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -726,10 +726,14 @@ static const struct seq_operations objec
};
DEFINE_SEQ_ATTRIBUTE(objects);
-static int __init kfence_debugfs_init(void)
+static int kfence_debugfs_init(void)
{
- struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
+ struct dentry *kfence_dir;
+ if (!READ_ONCE(kfence_enabled))
+ return 0;
+
+ kfence_dir = debugfs_create_dir("kfence", NULL);
debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
return 0;
@@ -883,6 +887,8 @@ static int kfence_init_late(void)
}
kfence_init_enable();
+ kfence_debugfs_init();
+
return 0;
}
Patches currently in stable-queue which might be from songmuchun@xxxxxxxxxxxxx are
queue-6.2/mm-kfence-fix-using-kfence_metadata-without-initialization-in-show_object.patch
