From patchwork Wed Dec 29 12:40:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12700862 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21251C433EF for ; Wed, 29 Dec 2021 12:40:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 382E76B0072; Wed, 29 Dec 2021 07:40:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3309B6B0073; Wed, 29 Dec 2021 07:40:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 21FA86B0074; Wed, 29 Dec 2021 07:40:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0115.hostedemail.com [216.40.44.115]) by kanga.kvack.org (Postfix) with ESMTP id 136A16B0072 for ; Wed, 29 Dec 2021 07:40:35 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id BDC3589B26 for ; Wed, 29 Dec 2021 12:40:34 +0000 (UTC) X-FDA: 78970790388.21.F5CBE04 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf26.hostedemail.com (Postfix) with ESMTP id 1E86E140003 for ; Wed, 29 Dec 2021 12:40:34 +0000 (UTC) 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 48C6B614A9; Wed, 29 Dec 2021 12:40:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AEF0C36AE7; Wed, 29 Dec 2021 12:40:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640781632; bh=JNtJWhL8T6Yw6jb+V2HcqwNvBrLooLiUovJs7iJkiJE=; h=From:To:Cc:Subject:Date:From; b=fm86xMaC9MeOy4RjPSKTCxE3SgGMcOoQNmpgxjPMOXctMo8C2UfsN4uSB1Zlc7TE4 m6V3OeyWA3p2n2IleCTbSQKsX4v8sURjbDFpqUqaaOzmis/yZyhZFG6TMBq7/bPHWa s4siX7GZL43RcGB+N02rVzQ3DkyIMP6XCdjx8yVMwHiKWVc/f2uqxxGzelXrfyMhS+ sPiel3BGwnrEqxNMNxbY8yPOvO1o59gRuQyv1fD2bM9yvn4s6SOoc2I/Tjhulr9Lgy r+s27M3t/SfBtfnkcpE+W+PQ0ZVi3bosNScBPLJayH1xFXFLS4x5RSFYUkPEHcPTbs 5yqfpardqsr7w== From: SeongJae Park To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park , stable@vger.kernel.org Subject: [PATCH] mm/damon/dbgfs: Fix 'struct pid' leaks in 'dbgfs_target_ids_write()' Date: Wed, 29 Dec 2021 12:40:29 +0000 Message-Id: <20211229124029.23348-1-sj@kernel.org> X-Mailer: git-send-email 2.17.1 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=fm86xMaC; spf=pass (imf26.hostedemail.com: domain of sj@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1E86E140003 X-Stat-Signature: pdpdxxu7mm3o7e1bmy9h77hnsxfpjkag X-HE-Tag: 1640781634-227582 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") Signed-off-by: SeongJae Park Cc: # 5.15.x --- mm/damon/dbgfs.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 489be9c830c4..751c7b835684 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -362,6 +362,7 @@ static ssize_t dbgfs_target_ids_write(struct file *file, 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; @@ -406,8 +407,12 @@ static ssize_t dbgfs_target_ids_write(struct file *file, 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)