+ mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch added to mm-unstable branch

+ mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mempool: skip slub_debug poisoning when KASAN is enabled
has been added to the -mm mm-unstable branch.  Its filename is
     mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@google.com>
Subject: mempool: skip slub_debug poisoning when KASAN is enabled
Date: Tue, 19 Dec 2023 23:28:57 +0100

With the changes in the following patch, KASAN starts saving its metadata
within freed mempool elements.

Thus, skip slub_debug poisoning and checking of mempool elements when
KASAN is enabled.  Corruptions of freed mempool elements will be detected
by KASAN anyway.

Link: https://lkml.kernel.org/r/98a4b1617e8ceeb266ef9a46f5e8c7f67a563ad2.1703024586.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mempool.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/mm/mempool.c~mempool-skip-slub_debug-poisoning-when-kasan-is-enabled
+++ a/mm/mempool.c
@@ -56,6 +56,10 @@ static void __check_element(mempool_t *p
 
 static void check_element(mempool_t *pool, void *element)
 {
+	/* Skip checking: KASAN might save its metadata in the element. */
+	if (kasan_enabled())
+		return;
+
 	/* Mempools backed by slab allocator */
 	if (pool->free == mempool_kfree) {
 		__check_element(pool, element, (size_t)pool->pool_data);
@@ -81,6 +85,10 @@ static void __poison_element(void *eleme
 
 static void poison_element(mempool_t *pool, void *element)
 {
+	/* Skip poisoning: KASAN might save its metadata in the element. */
+	if (kasan_enabled())
+		return;
+
 	/* Mempools backed by slab allocator */
 	if (pool->alloc == mempool_kmalloc) {
 		__poison_element(element, (size_t)pool->pool_data);
_

Patches currently in -mm which might be from andreyknvl@google.com are

kasan-rename-kasan_slab_free_mempool-to-kasan_mempool_poison_object.patch
kasan-move-kasan_mempool_poison_object.patch
kasan-document-kasan_mempool_poison_object.patch
kasan-add-return-value-for-kasan_mempool_poison_object.patch
kasan-introduce-kasan_mempool_unpoison_object.patch
kasan-introduce-kasan_mempool_poison_pages.patch
kasan-introduce-kasan_mempool_unpoison_pages.patch
kasan-clean-up-__kasan_mempool_poison_object.patch
kasan-save-free-stack-traces-for-slab-mempools.patch
kasan-clean-up-and-rename-____kasan_kmalloc.patch
kasan-introduce-poison_kmalloc_large_redzone.patch
kasan-save-alloc-stack-traces-for-mempool.patch
mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch
mempool-use-new-mempool-kasan-hooks.patch
mempool-introduce-mempool_use_prealloc_only.patch
kasan-add-mempool-tests.patch
kasan-rename-pagealloc-tests.patch
kasan-reorder-tests.patch
kasan-rename-and-document-kasan_unpoison_object_data.patch
skbuff-use-mempool-kasan-hooks.patch
io_uring-use-mempool-kasan-hook.patch