diff options
| author | SeongJae Park <sj@kernel.org> | 2025-07-20 11:58:22 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-28 16:31:03 +0200 |
| commit | 7c303fa1f311aadc17fa82b7bbf776412adf45de (patch) | |
| tree | 039d679ff129de760a7d961397cd9d3dc793ba19 | |
| parent | e35c822d6565e9d1332bc190766e4d223e6f1ae0 (diff) | |
mm/damon/ops-common: ignore migration request to invalid nodes
commit 7e6c3130690a01076efdf45aa02ba5d5c16849a0 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/damon/paddr.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 8813038abc6f..4120a73f4933 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -431,6 +431,10 @@ 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)); |