From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D39CC0502C for ; Sun, 28 Aug 2022 21:05:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229808AbiH1VFM (ORCPT ); Sun, 28 Aug 2022 17:05:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230062AbiH1VDj (ORCPT ); Sun, 28 Aug 2022 17:03:39 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50CB73120C; Sun, 28 Aug 2022 14:03:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5CD9F60E96; Sun, 28 Aug 2022 21:03:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 768BFC433C1; Sun, 28 Aug 2022 21:03:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1661720616; bh=r0PMKakWy5RBKt2gf4pcybO5cH02byXBhCaYbZj0d8U=; h=Date:To:From:Subject:From; b=J/8f3GVwfkWdWTTyoS6zNxkJIBWgIkGYuR/4/3R7EWD8x5dBbKrdYU2wJrO/58rE5 LuB6k7CgiFfvGkvCkX60LojBoZnR1bvUi7sAR9IgHPqbIWmkNNIJtZkAM3QZObdobq S9oQPqh/oHDrVPuQkLReqXOI83Gp6hF8aYh8wwRg= Date: Sun, 28 Aug 2022 14:03:35 -0700 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, sj@kernel.org, badari.pulavarty@intel.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-damon-dbgfs-avoid-duplicate-context-directory-creation.patch removed from -mm tree Message-Id: <20220828210336.768BFC433C1@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The quilt patch titled Subject: mm/damon/dbgfs: avoid duplicate context directory creation has been removed from the -mm tree. Its filename was mm-damon-dbgfs-avoid-duplicate-context-directory-creation.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Badari Pulavarty Subject: mm/damon/dbgfs: avoid duplicate context directory creation Date: Sun, 21 Aug 2022 18:08:53 +0000 When user tries to create a DAMON context via the DAMON debugfs interface with a name of an already existing context, the context directory creation fails but a new context is created and added in the internal data structure, due to absence of the directory creation success check. As a result, memory could leak and DAMON cannot be turned on. An example test case is as below: # cd /sys/kernel/debug/damon/ # echo "off" > monitor_on # echo paddr > target_ids # echo "abc" > mk_context # echo "abc" > mk_context # echo $$ > abc/target_ids # echo "on" > monitor_on <<< fails Return value of 'debugfs_create_dir()' is expected to be ignored in general, but this is an exceptional case as DAMON feature is depending on the debugfs functionality and it has the potential duplicate name issue. This commit therefore fixes the issue by checking the directory creation failure and immediately return the error in the case. Link: https://lkml.kernel.org/r/20220821180853.2400-1-sj@kernel.org Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts") Signed-off-by: Badari Pulavarty Signed-off-by: SeongJae Park Cc: [ 5.15.x] Signed-off-by: Andrew Morton --- mm/damon/dbgfs.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/damon/dbgfs.c~mm-damon-dbgfs-avoid-duplicate-context-directory-creation +++ a/mm/damon/dbgfs.c @@ -818,6 +818,9 @@ static int dbgfs_mk_context(char *name) return -ENOENT; new_dir = debugfs_create_dir(name, root); + /* Below check is required for a potential duplicated name case */ + if (IS_ERR(new_dir)) + return PTR_ERR(new_dir); dbgfs_dirs[dbgfs_nr_ctxs] = new_dir; new_ctx = dbgfs_new_ctx(); _ Patches currently in -mm which might be from badari.pulavarty@intel.com are