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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52C92C433EF for ; Sat, 25 Dec 2021 05:12:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E4E416B0085; Sat, 25 Dec 2021 00:12:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DFEEC6B0087; Sat, 25 Dec 2021 00:12:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CEE436B0088; Sat, 25 Dec 2021 00:12:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0168.hostedemail.com [216.40.44.168]) by kanga.kvack.org (Postfix) with ESMTP id BDC196B0085 for ; Sat, 25 Dec 2021 00:12:58 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 8DA1B8249980 for ; Sat, 25 Dec 2021 05:12:58 +0000 (UTC) X-FDA: 78955147236.04.3F5B788 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf03.hostedemail.com (Postfix) with ESMTP id 06A5420025 for ; Sat, 25 Dec 2021 05:12:57 +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 ams.source.kernel.org (Postfix) with ESMTPS id D3055B80B2D; Sat, 25 Dec 2021 05:12:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C01DC36AE5; Sat, 25 Dec 2021 05:12:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1640409175; bh=jwq1C0xCNOQZ4o6aepOLSPYYPk9cTF/tgIqKQoBxg34=; h=Date:From:To:Subject:In-Reply-To:From; b=xSA61ujtNjDkZtLPmLHfBT1+LxS6pJlEx5z4/wPNIzkseeNcv+WVWAq69gOWuqFFq akp2WTErizuLoHhgy46S4r8v952WtBksPb84YUcN4PY6xYWwQwiHup1HTEGgynsRVI FUCeyObq9KTOROLgioU7WDKAzKZVQ5NuuOYRKw4M= Date: Fri, 24 Dec 2021 21:12:54 -0800 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, sangwoob@amazon.com, sj@kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 8/9] mm/damon/dbgfs: protect targets destructions with kdamond_lock Message-ID: <20211225051254.qnNQD42Wg%akpm@linux-foundation.org> In-Reply-To: <20211224211127.30b60764d059ff3b0afea38a@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 06A5420025 X-Stat-Signature: 4ofr17q9x9nadsa348erqqncq5ot44a5 Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=xSA61ujt; spf=pass (imf03.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam10 X-HE-Tag: 1640409177-443254 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: From: SeongJae Park Subject: mm/damon/dbgfs: protect targets destructions with kdamond_lock DAMON debugfs interface iterates current monitoring targets in 'dbgfs_target_ids_read()' while holding the corresponding 'kdamond_lock'. However, it also destructs the monitoring targets in 'dbgfs_before_terminate()' without holding the lock. This can result in a use_after_free bug. This commit avoids the race by protecting the destruction with the corresponding 'kdamond_lock'. Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@kernel.org Reported-by: Sangwoo Bae Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") Signed-off-by: SeongJae Park Cc: [5.15.x] Signed-off-by: Andrew Morton --- mm/damon/dbgfs.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/damon/dbgfs.c~mm-damon-dbgfs-protect-targets-destructions-with-kdamond_lock +++ a/mm/damon/dbgfs.c @@ -650,10 +650,12 @@ static void dbgfs_before_terminate(struc if (!targetid_is_pid(ctx)) return; + mutex_lock(&ctx->kdamond_lock); damon_for_each_target_safe(t, next, ctx) { put_pid((struct pid *)t->id); damon_destroy_target(t); } + mutex_unlock(&ctx->kdamond_lock); } static struct damon_ctx *dbgfs_new_ctx(void) _