This is a note to let you know that I've just added the patch titled
kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
to the 5.11-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:
kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f9d79e8dce4077d3c6ab739c808169dfa99af9ef Mon Sep 17 00:00:00 2001
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Date: Fri, 12 Mar 2021 21:08:10 -0800
Subject: kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
commit f9d79e8dce4077d3c6ab739c808169dfa99af9ef upstream.
Currently, kasan_free_nondeferred_pages()->kasan_free_pages() is called
after debug_pagealloc_unmap_pages(). This causes a crash when
debug_pagealloc is enabled, as HW_TAGS KASAN can't set tags on an
unmapped page.
This patch puts kasan_free_nondeferred_pages() before
debug_pagealloc_unmap_pages() and arch_free_page(), which can also make
the page unavailable.
Link: https://lkml.kernel.org/r/24cd7db274090f0e5bc3adcdc7399243668e3171.1614987311.git.andreyknvl@xxxxxxxxxx
Fixes: 94ab5b61ee16 ("kasan, arm64: enable CONFIG_KASAN_HW_TAGS")
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1282,6 +1282,12 @@ static __always_inline bool free_pages_p
kernel_poison_pages(page, 1 << order);
/*
+ * With hardware tag-based KASAN, memory tags must be set before the
+ * page becomes unavailable via debug_pagealloc or arch_free_page.
+ */
+ kasan_free_nondeferred_pages(page, order);
+
+ /*
* arch_free_page() can make the page's contents inaccessible. s390
* does this. So nothing which can access the page's contents should
* happen after this.
@@ -1290,8 +1296,6 @@ static __always_inline bool free_pages_p
debug_pagealloc_unmap_pages(page, 1 << order);
- kasan_free_nondeferred_pages(page, order);
-
return true;
}
Patches currently in stable-queue which might be from andreyknvl@xxxxxxxxxx are
queue-5.11/kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
queue-5.11/kasan-fix-memory-corruption-in-kasan_bitops_tags-tes.patch
queue-5.11/kasan-fix-kasan_stack-dependency-for-hw_tags.patch
queue-5.11/arm64-kasan-fix-page_alloc-tagging-with-debug_virtual.patch
