From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 88AAA32C33A; Mon, 18 Aug 2025 17:31:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755538262; cv=none; b=DxqhXf3z7ySQyhO3vJ1Dg2Ir5vYarEc6doEyFCURuynZudZnoRW6yY4uyCqajkHt3imQ/hDSvEznrkuTUJy/3sPYhS+xl/wm05MlpvTkb7ZvYCFM40qh72CTL3ICIklMk+jhj7dy2P7EuHl/Ki3tE7+h/qnMKbkdp45E6QHnfA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755538262; c=relaxed/simple; bh=4Pjd9TNGOPRxXeRTGonj96aAUJIdna38eyaQvAHKeAM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=YA3/HLyxwU3ATojByqRMYsVQkdRrStkBVOBx9PqR7YFnKA8/rwoLtCJATKR0Y28Q2iH4cfaoCOVdpc/WN7h1uyW9r1N0mHp7+jJ1Jhwm0u0+eaWeSuvE09A+18gCUXJEnv82CUmg1CYk8EG/qrawBYhxM24SxmQRnlMQIR1gOjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rFHKJyBj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rFHKJyBj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB986C116C6; Mon, 18 Aug 2025 17:31:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755538262; bh=4Pjd9TNGOPRxXeRTGonj96aAUJIdna38eyaQvAHKeAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rFHKJyBjzeGrFzoLouOQOIgQCDBLjhjv844s3Vhx1jnWsPMTBNqqyoGzu+F6CUzBk htBQ3ZDDJ7BwU4PTDNEuVAfzkBtcdqkxoL0Z/t0kEAlMK+O1gMGxzpcFbIQy91ODKs NtcwZ+LDG0qGwPrA5u8/3vTF7EIvQ3aXWEYwFvDoJLy0+AVNGFU8dk10TIJlhgSgqf fsoKAS+0Qu4yuT4BRFHt2Uf1grsROGgYAbiuWuDAshzZCMnBYHerRNnGhaSJbLpSWt Bv4KpVvfMvQipqBVn89oU/0e4WlFgjq2bDMwvAbETUY56yjrZc0XDUAweTvGiqiS1z cgZQHVv4PQB2Q== From: SeongJae Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SeongJae Park , Joshua Hahn , Honggyu Kim , Hyeongtak Ji , Andrew Morton Subject: [PATCH 6.15.y] mm/damon/ops-common: ignore migration request to invalid nodes Date: Mon, 18 Aug 2025 10:30:58 -0700 Message-Id: <20250818173058.56921-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <2025081832-splendor-carve-f25b@gregkh> References: <2025081832-splendor-carve-f25b@gregkh> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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] [ 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 Reviewed-by: Joshua Hahn Cc: Honggyu Kim Cc: Hyeongtak Ji Cc: Signed-off-by: Andrew Morton (cherry picked from commit 7e6c3130690a01076efdf45aa02ba5d5c16849a0) Signed-off-by: SeongJae Park --- mm/damon/paddr.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 1b70d3f36046..32ee3739f1d2 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