FAILED: patch "[PATCH] mm/damon/ops-common: putback folios on invalid migrate nid" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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 <[email protected]>.

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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026081721-strainer-detract-6eed@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a Mon Sep 17 00:00:00 2001
From: liyouhong <[email protected]>
Date: Sun, 26 Jul 2026 09:48:15 +0800
Subject: [PATCH] mm/damon/ops-common: putback folios on invalid migrate nid

damon_pa_migrate() and damos_va_migrate() isolate folios into a local list and then call damon_migrate_pages(). When target_nid is invalid (including the scheme default NUMA_NO_NODE / -1), damon_migrate_pages() returns early without putting the folios back to the LRU.

Callers then discard the list head while those folios remain isolated with an extra reference taken by folio_isolate_lru(). The pages stay off the LRU for as long as the mapping exists (anon active+inactive counts drop while RSS does not), and the leftover references can pin the pages after the mapping is gone.

Put the folios back on the invalid-nid path so ignored migration requests still return them to the LRU.

index 6bdd1cfd3863..9c178c175832 100644
@@ -392,8 +392,15 @@ unsigned long damon_migrate_pages(struct list_head *folio_list, int target_nid)
 		return nr_migrated;
 
 	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
-			!node_state(target_nid, N_MEMORY))
+			!node_state(target_nid, N_MEMORY)) {
+		while (!list_empty(folio_list)) {
+			struct folio *folio = lru_to_folio(folio_list);
+
+			list_del(&folio->lru);
+			folio_putback_lru(folio);
+		}
 		return nr_migrated;
+	}
 
 	noreclaim_flag = memalloc_noreclaim_save();
 

From: liyouhong <[email protected]>

damon_pa_migrate() and damos_va_migrate() isolate folios into a local list and then call damon_migrate_pages(). When target_nid is invalid (including the scheme default NUMA_NO_NODE / -1), damon_migrate_pages() returns early without putting the folios back to the LRU.

Callers then discard the list head while those folios remain isolated with an extra reference taken by folio_isolate_lru(). The pages stay off the LRU for as long as the mapping exists (anon active+inactive counts drop while RSS does not), and the leftover references can pin the pages after the mapping is gone.

Put the folios back on the invalid-nid path so ignored migration requests still return them to the LRU.

---
 mm/damon/paddr.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

index 4120a73f49339..884042856f7ea 100644
@@ -432,8 +432,15 @@ static unsigned long damon_pa_migrate_pages(struct list_head *folio_list,
 		return nr_migrated;
 
 	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
-			!node_state(target_nid, N_MEMORY))
+			!node_state(target_nid, N_MEMORY)) {
+		while (!list_empty(folio_list)) {
+			struct folio *folio = lru_to_folio(folio_list);
+
+			list_del(&folio->lru);
+			folio_putback_lru(folio);
+		}
 		return nr_migrated;
+	}
 
 	noreclaim_flag = memalloc_noreclaim_save();
 

2.47.3

Queued for 6.12, thanks.

Thanks,
Sasha