FAILED: patch "[PATCH] mm/damon/ops-common: ignore migration request to invalid" failed to apply to 6.16-stable tree

FAILED: patch "[PATCH] mm/damon/ops-common: ignore migration request to invalid" failed to apply to 6.16-stable tree

[gregkh]

The patch below does not apply to the 6.16-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-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 7e6c3130690a01076efdf45aa02ba5d5c16849a0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025081831-singular-geologist-93a6@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 7e6c3130690a01076efdf45aa02ba5d5c16849a0 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Sun, 20 Jul 2025 11:58:22 -0700
Subject: [PATCH] mm/damon/ops-common: ignore migration request to invalid
 nodes

damon_migrate_pages() tries migration even if the target node is invalid.
If users mistakenly make such invalid requests via
DAMOS_MIGRATE_{HOT,COLD} action, the below kernel BUG can happen.

    [ 7831.883495] BUG: unable to handle page fault for address: 0000000000001f48
    [ 7831.884160] #PF: supervisor read access in kernel mode
    [ 7831.884681] #PF: error_code(0x0000) - not-present page
    [ 7831.885203] PGD 0 P4D 0
    [ 7831.885468] Oops: Oops: 0000 [#1] SMP PTI
    [ 7831.885852] CPU: 31 UID: 0 PID: 94202 Comm: kdamond.0 Not tainted 6.16.0-rc5-mm-new-damon+ #93 PREEMPT(voluntary)
    [ 7831.886913] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.el9 04/01/2014
    [ 7831.887777] RIP: 0010:__alloc_frozen_pages_noprof (include/linux/mmzone.h:1724 include/linux/mmzone.h:1750 mm/page_alloc.c:4936 mm/page_alloc.c:5137)
    [...]
    [ 7831.895953] Call Trace:
    [ 7831.896195]  <TASK>
    [ 7831.896397] __folio_alloc_noprof (mm/page_alloc.c:5183 mm/page_alloc.c:5192)
    [ 7831.896787] migrate_pages_batch (mm/migrate.c:1189 mm/migrate.c:1851)
    [ 7831.897228] ? __pfx_alloc_migration_target (mm/migrate.c:2137)
    [ 7831.897735] migrate_pages (mm/migrate.c:2078)
    [ 7831.898141] ? __pfx_alloc_migration_target (mm/migrate.c:2137)
    [ 7831.898664] damon_migrate_folio_list (mm/damon/ops-common.c:321 mm/damon/ops-common.c:354)
    [ 7831.899140] damon_migrate_pages (mm/damon/ops-common.c:405)
    [...]

Add a target node validity check in damon_migrate_pages().  The validity
check is stolen from that of do_pages_move(), which is being used for the
move_pages() system call.

Link: https://lkml.kernel.org/r/20250720185822.1451-1-sj@kernel.org
Fixes: b51820ebea65 ("mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion")	[6.11.x]
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
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 6a9797d1d7ff..99321ff5cb92 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -383,6 +383,10 @@ unsigned long damon_migrate_pages(struct list_head *folio_list, int target_nid)
 	if (list_empty(folio_list))
 		return nr_migrated;
 
+	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
+			!node_state(target_nid, N_MEMORY))
+		return nr_migrated;
+
 	noreclaim_flag = memalloc_noreclaim_save();
 
 	nid = folio_nid(lru_to_folio(folio_list));

[PATCH 6.16.y] mm/damon/ops-common: ignore migration request to invalid nodes

[SeongJae Park]

damon_migrate_pages() tries migration even if the target node is invalid.
If users mistakenly make such invalid requests via
DAMOS_MIGRATE_{HOT,COLD} action, the below kernel BUG can happen.

    [ 7831.883495] BUG: unable to handle page fault for address: 0000000000001f48
    [ 7831.884160] #PF: supervisor read access in kernel mode
    [ 7831.884681] #PF: error_code(0x0000) - not-present page
    [ 7831.885203] PGD 0 P4D 0
    [ 7831.885468] Oops: Oops: 0000 [#1] SMP PTI
    [ 7831.885852] CPU: 31 UID: 0 PID: 94202 Comm: kdamond.0 Not tainted 6.16.0-rc5-mm-new-damon+ #93 PREEMPT(voluntary)
    [ 7831.886913] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.el9 04/01/2014
    [ 7831.887777] RIP: 0010:__alloc_frozen_pages_noprof (include/linux/mmzone.h:1724 include/linux/mmzone.h:1750 mm/page_alloc.c:4936 mm/page_alloc.c:5137)
    [...]
    [ 7831.895953] Call Trace:
    [ 7831.896195]  <TASK>
    [ 7831.896397] __folio_alloc_noprof (mm/page_alloc.c:5183 mm/page_alloc.c:5192)
    [ 7831.896787] migrate_pages_batch (mm/migrate.c:1189 mm/migrate.c:1851)
    [ 7831.897228] ? __pfx_alloc_migration_target (mm/migrate.c:2137)
    [ 7831.897735] migrate_pages (mm/migrate.c:2078)
    [ 7831.898141] ? __pfx_alloc_migration_target (mm/migrate.c:2137)
    [ 7831.898664] damon_migrate_folio_list (mm/damon/ops-common.c:321 mm/damon/ops-common.c:354)
    [ 7831.899140] damon_migrate_pages (mm/damon/ops-common.c:405)
    [...]

Add a target node validity check in damon_migrate_pages().  The validity
check is stolen from that of do_pages_move(), which is being used for the
move_pages() system call.

Link: https://lkml.kernel.org/r/20250720185822.1451-1-sj@kernel.org
Fixes: b51820ebea65 ("mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion")	[6.11.x]
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 7e6c3130690a01076efdf45aa02ba5d5c16849a0)
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/paddr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 4102a8c5f992..578546ef74a0 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -476,6 +476,10 @@ static unsigned long damon_pa_migrate_pages(struct list_head *folio_list,
 	if (list_empty(folio_list))
 		return nr_migrated;
 
+	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
+			!node_state(target_nid, N_MEMORY))
+		return nr_migrated;
+
 	noreclaim_flag = memalloc_noreclaim_save();
 
 	nid = folio_nid(lru_to_folio(folio_list));
-- 
2.39.5