+ mempool-do-not-use-ksize-for-poisoning-fix.patch added to mm-unstable branch

+ mempool-do-not-use-ksize-for-poisoning-fix.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mempool-do-not-use-ksize-for-poisoning-fix
has been added to the -mm mm-unstable branch.  Its filename is
     mempool-do-not-use-ksize-for-poisoning-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mempool-do-not-use-ksize-for-poisoning-fix.patch

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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Vlastimil Babka <vbabka@suse.cz>
Subject: mempool-do-not-use-ksize-for-poisoning-fix

For slab mempools (not kmalloc), pool_data is not object size, but a
kmem_cache pointer; we need to extract the size via kmem_cache_size().

Link: https://lkml.kernel.org/r/13c4bd6e-09d3-efce-43a5-5a99be8bc96b@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Link: https://lore.kernel.org/all/20221031105514.GB69385@mutt/
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202210312110.1fe5d224-oliver.sang@intel.com
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mempool.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- a/mm/mempool.c~mempool-do-not-use-ksize-for-poisoning-fix
+++ a/mm/mempool.c
@@ -57,8 +57,10 @@ static void __check_element(mempool_t *p
 static void check_element(mempool_t *pool, void *element)
 {
 	/* Mempools backed by slab allocator */
-	if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
+	if (pool->free == mempool_kfree) {
 		__check_element(pool, element, (size_t)pool->pool_data);
+	} else if (pool->free == mempool_free_slab) {
+		__check_element(pool, element, kmem_cache_size(pool->pool_data));
 	} else if (pool->free == mempool_free_pages) {
 		/* Mempools backed by page allocator */
 		int order = (int)(long)pool->pool_data;
@@ -80,8 +82,10 @@ static void __poison_element(void *eleme
 static void poison_element(mempool_t *pool, void *element)
 {
 	/* Mempools backed by slab allocator */
-	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
+	if (pool->alloc == mempool_kmalloc) {
 		__poison_element(element, (size_t)pool->pool_data);
+	} else if (pool->alloc == mempool_alloc_slab) {
+		__poison_element(element, kmem_cache_size(pool->pool_data));
 	} else if (pool->alloc == mempool_alloc_pages) {
 		/* Mempools backed by page allocator */
 		int order = (int)(long)pool->pool_data;
@@ -111,8 +115,10 @@ static __always_inline void kasan_poison
 
 static void kasan_unpoison_element(mempool_t *pool, void *element)
 {
-	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
+	if (pool->alloc == mempool_kmalloc)
 		kasan_unpoison_range(element, (size_t)pool->pool_data);
+	else if (pool->alloc == mempool_alloc_slab)
+		kasan_unpoison_range(element, kmem_cache_size(pool->pool_data));
 	else if (pool->alloc == mempool_alloc_pages)
 		kasan_unpoison_pages(element, (unsigned long)pool->pool_data,
 				     false);
_

Patches currently in -mm which might be from vbabka@suse.cz are

mempool-do-not-use-ksize-for-poisoning-fix.patch