+ mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: swap: fix potensial buffer overflow in setup_clusters()
has been added to the -mm mm-new branch.  Its filename is
     mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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------------------------------------------------------
From: Kemeng Shi <shikemeng@huaweicloud.com>
Subject: mm: swap: fix potensial buffer overflow in setup_clusters()
Date: Thu, 22 May 2025 20:25:53 +0800

In setup_swap_map(), we only ensure badpages are in range (0, last_page]. 
As maxpages might be < last_page, setup_clusters() will encounter a buffer
overflow when a badpage is >= maxpages.

Only call inc_cluster_info_page() for badpage which is < maxpages to fix
the issue.

Link: https://lkml.kernel.org/r/20250522122554.12209-4-shikemeng@huaweicloud.com
Fixes: b843786b0bd01 ("mm: swapfile: fix SSD detection with swapfile on btrfs")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: <stable@vger.kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/mm/swapfile.c~mm-swap-fix-potensial-buffer-overflow-in-setup_clusters
+++ a/mm/swapfile.c
@@ -3208,9 +3208,13 @@ static struct swap_cluster_info *setup_c
 	 * and the EOF part of the last cluster.
 	 */
 	inc_cluster_info_page(si, cluster_info, 0);
-	for (i = 0; i < swap_header->info.nr_badpages; i++)
-		inc_cluster_info_page(si, cluster_info,
-				      swap_header->info.badpages[i]);
+	for (i = 0; i < swap_header->info.nr_badpages; i++) {
+		unsigned int page_nr = swap_header->info.badpages[i];
+
+		if (page_nr >= maxpages)
+			continue;
+		inc_cluster_info_page(si, cluster_info, page_nr);
+	}
 	for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++)
 		inc_cluster_info_page(si, cluster_info, i);
 
_

Patches currently in -mm which might be from shikemeng@huaweicloud.com are

mm-shmem-avoid-unpaired-folio_unlock-in-shmem_swapin_folio.patch
mm-shmem-add-missing-shmem_unacct_size-in-__shmem_file_setup.patch
mm-shmem-fix-potential-dead-loop-in-shmem_unuse.patch
mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0.patch
mm-shmem-remove-unneeded-xa_is_value-check-in-shmem_unuse_swap_entries.patch
mm-swap-move-nr_swap_pages-counter-decrement-from-folio_alloc_swap-to-swap_range_alloc.patch
mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop.patch
mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch
mm-swap-remove-stale-comment-stale-comment-in-cluster_alloc_swap_entry.patch