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 98D873F0AB3 for ; Thu, 19 Mar 2026 15:58:04 +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=1773935886; cv=pass; b=ow35s9CNbyU42DaYW6AIKd5OBtWofpCB8RrJhiLtwUQ3GiB6NQKeYXM3qBiIXCT0/9myMBHwcLdouDPKIQR7ArTCyk0Lt0MH093h9sJ3mHL9K+Z9DK7v1MvWQiBGDB4jg/csIGZn/dBU8bAzqOHiAufcW8qJMbyWFaCD/HF7eEg= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773935886; c=relaxed/simple; bh=JwbG40T0+NjSJqHxSwdAXN46+ePaQd8chNYzGTyPLxM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=AWyLPOKMzprg1eG2xTOa4al3HO8VhKhV+FQ+FLRU/dfi53oywxAfG3gzdaS2v7RqBnmH4wSQoSMHd78PTyHluAbu6WPND2wh+OlvCTukYiHaQzz1V7cpt7bia0e2RpgJ/X8EGW0pK7NeiH5jJRscGe9Sh5begvzVWk5+fKEsrFo= 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=W5gcWnu/; 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="W5gcWnu/" ARC-Seal: i=1; a=rsa-sha256; t=1773935868; cv=none; d=zohomail.eu; s=zohoarc; b=c+tKqOHY9UPTynVSBbutAl+9RnHzVGguG2Um28Y7dXBKuOWFS1y7jnvi/52w0+QfEFHdrddMrknOOSKHCqwIPHWZ8rbXdPIpMDbWxrAfmjz/KCSue4h2kGYKHBIR7Hk4/IMRjluq4REqhbGoKI5bFDblcOHUpg00ic5bwaNZzKY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.eu; s=zohoarc; t=1773935868; 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=IqBZZsdChXPych6lUYI4fPOHNYXnLYcU1he98Py/HTM=; b=KguRJssY07DB9GtFnwQrBywG8WzY9Lmd0r4H5hR8QwsvyKAPEdOHNw2SOGaAC3HIgANTnmR8ZgK6od0S4UJm8Ss/ezcAimhUnaYlcsIguxpzIa07UGBQVS9lRUla70oo6WCIrOYprQw4vRigydSfUFfc6rWlaI5QiB6XsYBLxjo= 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=1773935868; 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=IqBZZsdChXPych6lUYI4fPOHNYXnLYcU1he98Py/HTM=; b=W5gcWnu/w4EL90obqxJ2PnFbcQYOeauhiDKhqN1sO6UBQ5uZBb1ofNh0Wz5t1uOf h+AJCppag9NSvtLfHBWi3q/8E2SsGvP0NypykQuMnJYa/zBqOxy1b+v5dR76b1wBvVI eWIE3hzRkPLnt9EtTICS2CbkErWJ80esNjmkU4YY= Received: by mx.zoho.eu with SMTPS id 1773935865417260.7882034743719; 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 2/4] mm/damon/sysfs: check contexts->nr before clear_schemes_tried_regions Date: Thu, 19 Mar 2026 15:57:40 +0000 Message-Id: <20260319155742.186627-3-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" The CLEAR_SCHEMES_TRIED_REGIONS command accesses contexts_arr[0] without verifying nr_contexts >=3D 1, causing a NULL pointer dereference when no context is configured. 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 b573b9d60784..36ad2e8956c9 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1769,6 +1769,8 @@ static int damon_sysfs_handle_cmd(enum damon_sysfs_cm= d cmd, case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: return damon_sysfs_update_schemes_tried_regions(kdamond, false); case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS: + if (kdamond->contexts->nr !=3D 1) + return -EINVAL; return damon_sysfs_schemes_clear_regions( kdamond->contexts->contexts_arr[0]->schemes); case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS: --=20 2.34.1