From patchwork Fri Dec 31 04:12:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 529621 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 7E0C5C4332F for ; Fri, 31 Dec 2021 04:12:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242667AbhLaEMi (ORCPT ); Thu, 30 Dec 2021 23:12:38 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:32822 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231222AbhLaEMi (ORCPT ); Thu, 30 Dec 2021 23:12:38 -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 048E4B81D4B; Fri, 31 Dec 2021 04:12:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5ACFEC36AE9; Fri, 31 Dec 2021 04:12:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1640923955; bh=qAa71we+OzH5frizipYFiM2+rzEExaMHymKmGW3O0VY=; h=Date:From:To:Subject:In-Reply-To:From; b=YD+OR0pTQXCDeCTH0vi2rQScST1fUXVhUHIAxKRL+SiVcc5hI3KWx2aAJ7Efmhnmf wfFw3503EbJDxDS1icFXf41aZpU8CehX7LvyIXzBQpYYG8XXFc4Gwe0U3lwDzqZfB0 8x5Hp1vNfYl9I1t5UGD0iFX9QhkSjmEUKZDJ5IyA= Date: Thu, 30 Dec 2021 20:12:34 -0800 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, sj@kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 2/2] mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()' Message-ID: <20211231041234.50dCet98O%akpm@linux-foundation.org> In-Reply-To: <20211230201202.d9bcb24678cc3d9d503579a0@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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)