From nobody Mon Apr 6 11:53:09 2026 Received: from sender-of-o55.zoho.eu (sender-of-o55.zoho.eu [136.143.169.55]) (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 77B283EBF16 for ; Thu, 19 Mar 2026 15:58:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.169.55 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773935883; cv=pass; b=ZZnXuYGPMTnVWCtwO/B2DayqnjnwOV7gZjRW4zjcImK/2D1PTH/4qK0pma5X4FvvPKNOtgoZ2ktJAgWBdXjkZ2tI9QMRCRqNtkjFIYV75MzmYQoTeT//PHtKA0epylduu3tXEPtoI1u4pQGfzkQOzv2fNDiYxlQoBPLyN5hErtw= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773935883; c=relaxed/simple; bh=47Ps4uc1aNE8vYAe60YuDpBgoZTPi8UZ64vuMeXP3YU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=lgum7Y9pJF4GqvZT+TlLvd4rHmDmjw1dZzh5fnu8Iql4injA66GE9g9bzn0MvVhTAqTD0B6JRGzLdT3HfTPXpTqG2/r8llUQLmfdaL1SuQ1xN1ecn/USE4q7MqdyoRbqix6rRQXFg5Db5TlO3p1EoNM93p/aERuDseVfVGyFVGM= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=objecting.org; spf=pass smtp.mailfrom=objecting.org; dkim=pass (1024-bit key) header.d=objecting.org header.i=objecting@objecting.org header.b=jziCpude; arc=pass smtp.client-ip=136.143.169.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=objecting.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=objecting.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=objecting.org header.i=objecting@objecting.org header.b="jziCpude" ARC-Seal: i=1; a=rsa-sha256; t=1773935866; cv=none; d=zohomail.eu; s=zohoarc; b=cZWR/Rkxj1mC+DXgVZG57Be1vldOsmajFeB0+WgVBbAWDLVaEyJUWS0DssGHHobkV9JlaC9yQZMWmCEKGNcWNvSH8xbtdsIZ7kOi7oXEBQMtvJcKYTydh6nr25mQUNGwzAaw7+/uYT94NMGQO08X/kepJtyDARH+8uqjjPlHVKo= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.eu; s=zohoarc; t=1773935866; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=VCdnk7LCAdQl2Oinq44p2WouG2Ln6vJSbhR4GoqiOIc=; b=FpY9eFVneWtMNhwTt6wg/IjSOUw9LAVw7w2LP5frop0WtrtvhVW1APRu6QcLEZNZgFB60nQvfGy6qEG1M7ReqtYcbkupjKnT23hvijoWc8TdMK9eXx7a+rxiO7glkQYICGGFnaS5j31doVRRzGK2ctk/QgqwujH96ahDPH0YSU8= ARC-Authentication-Results: i=1; mx.zohomail.eu; dkim=pass header.i=objecting.org; spf=pass smtp.mailfrom=objecting@objecting.org; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1773935866; s=zmail; d=objecting.org; i=objecting@objecting.org; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-Id:Message-Id:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Reply-To; bh=VCdnk7LCAdQl2Oinq44p2WouG2Ln6vJSbhR4GoqiOIc=; b=jziCpudeDNVDmPyr3561UEvWdaVDVwTSd95V9uGmdiN1TUKpqm+em7I5nGHSKs3g fF40Zk/ylVrPhxFQ6vJwZzd8A7iuGK/uT0TCMvDULjT98mBA39e8wG7ZfidoAJonY3d aDy0amaHOZSDFGU9bCZ+zWvyKBW3o8zILKvv1ORE= Received: by mx.zoho.eu with SMTPS id 1773935865996405.19165630086957; Thu, 19 Mar 2026 16:57:45 +0100 (CET) From: Josh Law To: sj@kernel.org, akpm@linux-foundation.org Cc: damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Josh Law Subject: [PATCH 3/4] mm/damon/sysfs: check contexts->nr in update_schemes_tried_regions Date: Thu, 19 Mar 2026 15:57:41 +0000 Message-Id: <20260319155742.186627-4-objecting@objecting.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260319155742.186627-1-objecting@objecting.org> References: <20260319155742.186627-1-objecting@objecting.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External Content-Type: text/plain; charset="utf-8" damon_sysfs_update_schemes_tried_regions() and its callback damon_sysfs_schemes_tried_regions_upd_one() access contexts_arr[0] without verifying nr_contexts >=3D 1. This can NULL deref if damon_ctx is non-NULL (preserved after stop) but nr_contexts has been set to 0. Add the missing check. Signed-off-by: Josh Law --- mm/damon/sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index 36ad2e8956c9..ddcdc4e35b27 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1731,6 +1731,8 @@ static int damon_sysfs_update_schemes_tried_regions( =20 if (!ctx) return -EINVAL; + if (sysfs_kdamond->contexts->nr !=3D 1) + return -EINVAL; =20 damon_sysfs_schemes_clear_regions( sysfs_kdamond->contexts->contexts_arr[0]->schemes); --=20 2.34.1