This is a note to let you know that I've just added the patch titled
mm: kfence: fix handling discontiguous page
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-handling-discontiguous-page.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 1f2803b2660f4b04d48d065072c0ae0c9ca255fd Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Date: Thu, 23 Mar 2023 10:50:03 +0800
Subject: mm: kfence: fix handling discontiguous page
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
commit 1f2803b2660f4b04d48d065072c0ae0c9ca255fd upstream.
The struct pages could be discontiguous when the kfence pool is allocated
via alloc_contig_pages() with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.
This may result in setting PG_slab and memcg_data to a arbitrary
address (may be not used as a struct page), which in the worst case
might corrupt the kernel.
So the iteration should use nth_page().
Link: https://lkml.kernel.org/r/20230323025003.94447-1-songmuchun@xxxxxxxxxxxxx
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Reviewed-by: Kefeng Wang <wangkefeng.wang@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 | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -556,7 +556,7 @@ static unsigned long kfence_init_pool(vo
* enters __slab_free() slow-path.
*/
for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
- struct slab *slab = page_slab(&pages[i]);
+ struct slab *slab = page_slab(nth_page(pages, i));
if (!i || (i % 2))
continue;
@@ -602,7 +602,7 @@ static unsigned long kfence_init_pool(vo
reset_slab:
for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
- struct slab *slab = page_slab(&pages[i]);
+ struct slab *slab = page_slab(nth_page(pages, i));
if (!i || (i % 2))
continue;
Patches currently in stable-queue which might be from songmuchun@xxxxxxxxxxxxx are
queue-6.2/mm-kfence-fix-handling-discontiguous-page.patch
queue-6.2/mm-kfence-fix-pg_slab-and-memcg_data-clearing.patch
