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

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

[gregkh]

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 <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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --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 <liyouhong@kylinos.cn>
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.

Link: https://lore.kernel.org/20260726014815.1280757-1-dayou5941@163.com
Fixes: 7e6c3130690a ("mm/damon/ops-common: ignore migration request to invalid nodes")
Assisted-by: Cursor:grok-4.5
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: liyouhong <liyouhong@kylinos.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index 6bdd1cfd3863..9c178c175832 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -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();
 

[PATCH 6.12.y] mm/damon/ops-common: putback folios on invalid migrate nid

[SJ Park]

From: liyouhong <liyouhong@kylinos.cn>

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.

Link: https://lore.kernel.org/20260726014815.1280757-1-dayou5941@163.com
Fixes: 7e6c3130690a ("mm/damon/ops-common: ignore migration request to invalid nodes")
Assisted-by: Cursor:grok-4.5
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: liyouhong <liyouhong@kylinos.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a)
Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/paddr.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 4120a73f49339..884042856f7ea 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -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

Re: [PATCH 6.12.y] mm/damon/ops-common: putback folios on invalid migrate nid

[sashiko-bot]

> From: liyouhong <liyouhong@kylinos.cn>
> 
> 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.
> 
> Link: https://lore.kernel.org/20260726014815.1280757-1-dayou5941@163.com
> Fixes: 7e6c3130690a ("mm/damon/ops-common: ignore migration request to invalid nodes")
> Assisted-by: Cursor:grok-4.5
> Reviewed-by: SJ Park <sj@kernel.org>
> Signed-off-by: liyouhong <liyouhong@kylinos.cn>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> (cherry picked from commit 5deb65c34e682e7c5f5df417a70e223e8fcc5f5a)
> Signed-off-by: SJ Park <sj@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260818062518.91960-1-sj@kernel.org?part=1

Re: [PATCH 6.12.y] mm/damon/ops-common: putback folios on invalid migrate nid

[Sasha Levin]

On Mon, Aug 17, 2026 at 11:25:18PM -0700, SJ Park wrote:
> [PATCH 6.12.y] mm/damon/ops-common: putback folios on invalid migrate nid

Queued for 6.12, thanks.

-- 
Thanks,
Sasha