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 15B6CC433EF for ; Sun, 26 Dec 2021 10:26:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 49BDD6B0073; Sun, 26 Dec 2021 05:26:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 44B8F6B0074; Sun, 26 Dec 2021 05:26:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 33B2A6B007D; Sun, 26 Dec 2021 05:26:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0003.hostedemail.com [216.40.44.3]) by kanga.kvack.org (Postfix) with ESMTP id 20E886B0073 for ; Sun, 26 Dec 2021 05:26:39 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id C02308848F for ; Sun, 26 Dec 2021 10:26:38 +0000 (UTC) X-FDA: 78959566476.18.B879397 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf07.hostedemail.com (Postfix) with ESMTP id 661C640044 for ; Sun, 26 Dec 2021 10:26:38 +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 94362B80D8A; Sun, 26 Dec 2021 10:26:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4CCCC36AE9; Sun, 26 Dec 2021 10:26:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640514395; bh=c01Y1sVJff7yPWEv/LS6XlE+5QNdrrtxSt0y+lgu7bc=; h=From:To:Cc:Subject:Date:From; b=RWi0TpKKCgFlzCG3UWsVPVUILW2hZm29QHyuwbWZpypalvXYp7Luyaqy1Xp28TnE2 OmMZkgFmM9ijs/lxd+JoH3USCMXpDSgcIPSegiZk5vW9cbfyrrt9qQQc6MT43kg9BB n8KibIQFeFdoBV8Fq9or59FBRgEw2Z5grRdxuy7uvE+HthuUGyjto8sdE47OJnbdSr F0JY7Av/XOYretAXqz67GWhD6sycRQrfFVuG4bO8undd8omuRbr18lEACKMaXg/rgo Pq+bbHBGJXcp8Jb6plLSMatTVVbQC2Ids+Eu2DkjRexwZ6yebvLMTmZjkCW+0xwbTb 8vcJDE7TZGXPA== From: SeongJae Park To: stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park , Linus Torvalds Subject: [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock Date: Sun, 26 Dec 2021 10:26:32 +0000 Message-Id: <20211226102632.836-1-sj@kernel.org> X-Mailer: git-send-email 2.17.1 Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=RWi0TpKK; spf=pass (imf07.hostedemail.com: domain of sj@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Queue-Id: 661C640044 X-Stat-Signature: fkim8mi36115b3ska5bg1fo644wyasha X-Rspamd-Server: rspam04 X-HE-Tag: 1640514398-323959 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: commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream. 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 Signed-off-by: Linus Torvalds --- This is a backport of a DAMON fix that merged in the mainline, for v5.15.x stable series. mm/damon/dbgfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index f94d19a690df..d3bc110430f9 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -309,10 +309,12 @@ static int dbgfs_before_terminate(struct damon_ctx *ctx) if (!targetid_is_pid(ctx)) return 0; + 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); return 0; } -- 2.17.1