From 0e9a8550f320db944e4cf036d93c5debf0e574a7 Mon Sep 17 00:00:00 2001
From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Fri, 21 Jun 2024 13:35:01 +0200
Subject: [PATCH] mm: slub: let KMSAN access metadata

Building the kernel with CONFIG_SLUB_DEBUG and CONFIG_KMSAN causes KMSAN
to complain about touching redzones in kfree().

Fix by extending the existing KASAN-related metadata_access_enable() and
metadata_access_disable() functions to KMSAN.

Link: https://lkml.kernel.org/r/20240621113706.315500-18-iii@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/slub.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index dbe8a6303937a..10e396e1d495e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -829,10 +829,12 @@ static int disable_higher_order_debug;
 static inline void metadata_access_enable(void)
 {
 	kasan_disable_current();
+	kmsan_disable_current();
 }
 
 static inline void metadata_access_disable(void)
 {
+	kmsan_enable_current();
 	kasan_enable_current();
 }
 
-- 
2.50.1