From patchwork Wed Dec 29 23:23:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 528965 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 02F6AC433EF for ; Wed, 29 Dec 2021 23:23:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233181AbhL2XXF (ORCPT ); Wed, 29 Dec 2021 18:23:05 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:47620 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233152AbhL2XXE (ORCPT ); Wed, 29 Dec 2021 18:23:04 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 38C70B817AB; Wed, 29 Dec 2021 23:23:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB71FC36AEA; Wed, 29 Dec 2021 23:23:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1640820181; bh=BXG18Sw1yVHCdB15AVt+Dqe/tked87k4pz322bxIyX0=; h=Date:From:To:Subject:From; b=on+fkySPLFbyRIZLhT3rFavU7yE8rMs6DnhD5N6/xhE/BuZw9rgmc3HMzCDGscL+i hHII2/L2KaHPfQ2F655/55E/qTQvU5NWvKrFLefUSxiiYpKRmx9Bu1SmEF7yKRyZbg Q0h5vfxJx/5zlnzXfdx24H+Q66OEIn8bG0rUs23E= Date: Wed, 29 Dec 2021 15:23:02 -0800 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, stable@vger.kernel.org, sj@kernel.org Subject: + mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch added to -mm tree Message-ID: <20211229232302.2rP0w%akpm@linux-foundation.org> User-Agent: s-nail v14.9.10 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()' has been added to the -mm tree. Its filename is mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: SeongJae Park Subject: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()' DAMON debugfs interface increases the reference counts of 'struct pid's for targets from the 'target_ids' file write callback ('dbgfs_target_ids_write()'), but decreases the counts only in DAMON monitoring termination callback ('dbgfs_before_terminate()'). Therefore, when 'target_ids' file is repeatedly written without DAMON monitoring start/termination, the reference count is not decreased and therefore memory for the 'struct pid' cannot be freed. This commit fixes this issue by decreasing the reference counts when 'target_ids' is written. Link: https://lkml.kernel.org/r/20211229124029.23348-1-sj@kernel.org Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") Signed-off-by: SeongJae Park Cc: [5.15+] Signed-off-by: Andrew Morton --- mm/damon/dbgfs.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/damon/dbgfs.c~mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write +++ a/mm/damon/dbgfs.c @@ -353,6 +353,7 @@ static ssize_t dbgfs_target_ids_write(st const char __user *buf, size_t count, loff_t *ppos) { struct damon_ctx *ctx = file->private_data; + struct damon_target *t, *next_t; bool id_is_pid = true; char *kbuf, *nrs; unsigned long *targets; @@ -397,8 +398,12 @@ static ssize_t dbgfs_target_ids_write(st goto unlock_out; } - /* remove targets with previously-set primitive */ - damon_set_targets(ctx, NULL, 0); + /* remove previously set targets */ + damon_for_each_target_safe(t, next_t, ctx) { + if (targetid_is_pid(ctx)) + put_pid((struct pid *)t->id); + damon_destroy_target(t); + } /* Configure the context for the address space type */ if (id_is_pid)