[merged mm-hotfixes-stable] mm-memory_hotplug-fix-memory-block-reference-leak-on-remove.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm/memory_hotplug: fix memory block reference leak on remove
has been removed from the -mm tree.  Its filename was
     mm-memory_hotplug-fix-memory-block-reference-leak-on-remove.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/memory_hotplug: fix memory block reference leak on remove
Date: Tue, 28 Apr 2026 16:52:17 +0800

Patch series "mm: Fix memory block leaks and locking", v2.

This series fixes two memory block device reference leaks and one locking
issue around the per-memory_block hwpoison counter.


This patch (of 2):

remove_memory_blocks_and_altmaps() looks up each memory block with
find_memory_block(), which acquires a reference to the memory block
device.

That reference is never dropped on this path, resulting in a leaked device
reference when removing memory blocks and their altmaps.  Drop the
reference after retrieving mem->altmap and clearing mem->altmap, before
removing the memory block device.

Link: https://lore.kernel.org/20260428085219.1316047-1-songmuchun@bytedance.com
Link: https://lore.kernel.org/20260428085219.1316047-2-songmuchun@bytedance.com
Fixes: 6b8f0798b85a ("mm/memory_hotplug: split memmap_on_memory requests across memblocks")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Huang, Ying" <huang.ying.caritas@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/memory_hotplug.c~mm-memory_hotplug-fix-memory-block-reference-leak-on-remove
+++ a/mm/memory_hotplug.c
@@ -1422,6 +1422,8 @@ static void remove_memory_blocks_and_alt
 
 		altmap = mem->altmap;
 		mem->altmap = NULL;
+		/* drop the ref. we got via find_memory_block() */
+		put_device(&mem->dev);
 
 		remove_memory_block_devices(cur_start, memblock_size);
 
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-sparse-remove-sparse-buffer-pre-allocation-mechanism.patch
mm-sparse-vmemmap-fix-vmemmap-accounting-underflow.patch
mm-memory_hotplug-fix-incorrect-altmap-passing-in-error-path.patch
mm-sparse-vmemmap-pass-pgmap-argument-to-memory-deactivation-paths.patch
mm-sparse-vmemmap-fix-dax-vmemmap-accounting-with-optimization.patch
mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages.patch
mm-mm_init-fix-uninitialized-struct-pages-for-zone_device.patch
mm-memory_hotplug-factor-out-altmap-freeing-checks.patch
drivers-base-memory-make-memory-block-get-put-explicit.patch