FAILED: patch "[PATCH] dm vdo indexer: prevent delta list overflow on load" failed to apply to 5.15-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 936293c9f3f4f2a0d1b80df9332e96c552ac3b37
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107055832-failed-5.15-936293c9f3f4@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 936293c9f3f4f2a0d1b80df9332e96c552ac3b37 Mon Sep 17 00:00:00 2001
From: Matthew Sakai <msakai@redhat.com>
Date: Tue, 11 Aug 2026 15:02:33 -0400
Subject: [PATCH] dm vdo indexer: prevent delta list overflow on load

Check for corrupted delta lists sizes that overflow the
memory available for the delta_lists. An overflow can
cause the delta list data to be written outside the
reserved delta memory space.

Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
---
 drivers/md/dm-vdo/indexer/delta-index.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-vdo/indexer/delta-index.c b/drivers/md/dm-vdo/indexer/delta-index.c
index b288749067dee..257612b81a9d9 100644
--- a/drivers/md/dm-vdo/indexer/delta-index.c
+++ b/drivers/md/dm-vdo/indexer/delta-index.c
@@ -800,7 +800,7 @@ static void compute_new_list_offsets(struct delta_zone *delta_zone, u32 growing_
 		(delta_zone->size * BITS_PER_BYTE - delta_lists[tail_guard_index].size);
 }
 
-static void rebalance_lists(struct delta_zone *delta_zone)
+static int rebalance_lists(struct delta_zone *delta_zone)
 {
 	struct delta_list *delta_lists;
 	u32 i;
@@ -811,9 +811,17 @@ static void rebalance_lists(struct delta_zone *delta_zone)
 	for (i = 0; i <= delta_zone->list_count + 1; i++)
 		used_space += get_delta_list_byte_size(&delta_lists[i]);
 
+	if (delta_zone->size < used_space) {
+		return vdo_log_warning_strerror(UDS_CORRUPT_DATA,
+						"delta zone lists overflow zone size %zu",
+						delta_zone->size);
+	}
+
 	compute_new_list_offsets(delta_zone, 0, 0, used_space);
 	for (i = 1; i <= delta_zone->list_count + 1; i++)
 		delta_lists[i].start = delta_zone->new_offsets[i];
+
+	return UDS_SUCCESS;
 }
 
 /* Start restoring a delta index from multiple input streams. */
@@ -941,8 +949,11 @@ int uds_start_restoring_delta_index(struct delta_index *delta_index,
 	}
 
 	/* Prepare each zone to start receiving the delta list data. */
-	for (z = 0; z < delta_index->zone_count; z++)
-		rebalance_lists(&delta_index->delta_zones[z]);
+	for (z = 0; z < delta_index->zone_count; z++) {
+		result = rebalance_lists(&delta_index->delta_zones[z]);
+		if (result != UDS_SUCCESS)
+			return result;
+	}
 
 	return UDS_SUCCESS;
 }
-- 
2.53.0