From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2D9FB370AE3; Thu, 13 Aug 2026 03:50:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786593012; cv=none; b=egykkP3J+T+pyyQKOMzVYT6tUuwuHZxHHuW5xNbIsYusa5wpYurOqqRACCqu946wDLXWh/QODh8B3ped3IiFS39AsO8rgL0dk3I+POsYhsgaqBbaZu3tAfYkhJlBjdoIu9LPLs8MbhYEnp46bcB0lXFY/fhWUNpVydln9KLWG6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786593012; c=relaxed/simple; bh=mj11QH1OehidAc4GPX+bN8d559dYdSB4IO5jIUf5aNc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CiiDARyYiHzNa7McNt6zeQT0b0rPBdCE9zsEBzd+w6+DMFvert7W9U9BVi4vjyekxIT1G09kpaSn1q3vRjcVNaNSB/3y8Ske1n5dXMbael2BIIodGx7MLYNhTMcwEY8LHdIrK19jCiAmK/JzIr5JkW4v3HNTyTPBQh8/54AhryM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iJoGGSdG; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iJoGGSdG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C05661F00A3D; Thu, 13 Aug 2026 03:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786593008; bh=c9oXf7EAMULfNbhY5cYkXmrBshcuP/mpp00wWMiTWfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iJoGGSdGaEjb4GhhyfrN/DoXc4RJ8drILlJO9rtj/6VSiBf5E350SajVv0HD7Dsn/ kivaaLfRnNabpYQPi1uHU6nMutuuSvoqzhK3UieLdJb2v4whSYLf1pHgqRbXfa93mv rgpFFMK25+A76cfUDRiOlFBnP+eL42WhFwclzR6QhI2VcA0Su7ANfIzoNn60XU2M9s xNQ+I+bJWMBVoky87N81qfDWJ1hV4tdhdX2Dn/XyaY79wNvlioBm1tQllB643agRp1 EuQS5htblur55P9VnQEqKfOdOvJ8T3cKDxlboiZfngUq+6msFNHcPF5zbsVniw3rNi uh0OLA851Hvjw== From: SJ Park To: Cc: SJ Park , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 1/4] mm/damon/core: handle NULL ctx parameter in damon_call() Date: Wed, 12 Aug 2026 20:49:56 -0700 Message-ID: <20260813035001.97364-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260813035001.97364-1-sj@kernel.org> References: <20260813035001.97364-1-sj@kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When NULL damon_ctx pointer parameter is passed, damon_call() could do NULL dereference. The caller is responsible to avoid that. It is easy to forget, and there are many damon_call() callers. Meanwhile, damon_call() is never meant to be performance critical. It uses mutex and completion. Add the NULL pointer check inside damon_call() so that callers can pass the parameter without NULL checks. Signed-off-by: SJ Park --- mm/damon/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 92631a36d7b51..5882f9c94c47f 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -2188,6 +2188,8 @@ int damon_kdamond_pid(struct damon_ctx *ctx) */ int damon_call(struct damon_ctx *ctx, struct damon_call_control *control) { + if (!ctx) + return -EINVAL; if (!control->repeat) init_completion(&control->completion); control->canceled = false; -- 2.47.3