From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,stable@vger.kernel.org,senozhatsky@chromium.org,minchan@kernel.org,mark-pk.tsai@mediatek.com,syoshida@redhat.com,akpm@linux-foundation.org
Subject: [merged mm-stable] mm-zsmalloc-copy-kmsan-metadata-in-zs_page_migrate.patch removed from -mm tree
Date: Sat, 28 Mar 2026 17:42:33 -0700 [thread overview]
Message-ID: <20260329004233.CF588C4CEF7@smtp.kernel.org> (raw)
The quilt patch titled
Subject: mm/zsmalloc: copy KMSAN metadata in zs_page_migrate()
has been removed from the -mm tree. Its filename was
mm-zsmalloc-copy-kmsan-metadata-in-zs_page_migrate.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Shigeru Yoshida <syoshida@redhat.com>
Subject: mm/zsmalloc: copy KMSAN metadata in zs_page_migrate()
Date: Sat, 21 Mar 2026 22:29:11 +0900
zs_page_migrate() uses copy_page() to copy the contents of a zspage page
during migration. However, copy_page() is not instrumented by KMSAN, so
the shadow and origin metadata of the destination page are not updated.
As a result, subsequent accesses to the migrated page are reported as
use-after-free by KMSAN, despite the data being correctly copied.
Add a kmsan_copy_page_meta() call after copy_page() to propagate the KMSAN
metadata to the new page, matching what copy_highpage() does internally.
Link: https://lkml.kernel.org/r/20260321132912.93434-1-syoshida@redhat.com
Fixes: afb2d666d025 ("zsmalloc: use copy_page for full page copy")
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/zsmalloc.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/zsmalloc.c~mm-zsmalloc-copy-kmsan-metadata-in-zs_page_migrate
+++ a/mm/zsmalloc.c
@@ -1753,6 +1753,7 @@ static int zs_page_migrate(struct page *
*/
d_addr = kmap_local_zpdesc(newzpdesc);
copy_page(d_addr, s_addr);
+ kmsan_copy_page_meta(zpdesc_page(newzpdesc), zpdesc_page(zpdesc));
kunmap_local(d_addr);
for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE;
_
Patches currently in -mm which might be from syoshida@redhat.com are
reply other threads:[~2026-03-29 0:42 UTC|newest]
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