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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEB28C4167B for ; Tue, 31 Oct 2023 17:50:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231511AbjJaRua (ORCPT ); Tue, 31 Oct 2023 13:50:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236433AbjJaRu3 (ORCPT ); Tue, 31 Oct 2023 13:50:29 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DD8DA2 for ; Tue, 31 Oct 2023 10:50:27 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0EF7C433C7; Tue, 31 Oct 2023 17:50:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698774627; bh=4H1KD4EIJqyj4jWsfqDh//7hBjCmlLfxS6FDIihUkio=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X1NC+Izfmra6GPjr7mt3drKQ3ws+BRULq+YopPK0fK/UuLyVVSOY06z0XuK+duzo/ IVvryb59bvMNQTHpORS575HadQSEmzPn+QVn+60v6+aDIeeWZMBGetxxmGj3+Boeg9 KDkvlmBXvo4eNzn8lVO9jgm0wa0X3e95CME79vlQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, SeongJae Park , Andrew Morton Subject: [PATCH 6.5 111/112] mm/damon/sysfs: check DAMOS regions update progress from before_terminate() Date: Tue, 31 Oct 2023 18:01:52 +0100 Message-ID: <20231031165904.762790861@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231031165901.318222981@linuxfoundation.org> References: <20231031165901.318222981@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: SeongJae Park commit 76b7069bcc89dec33f03eb08abee165d0306b754 upstream. DAMON_SYSFS can receive DAMOS tried regions update request while kdamond is already out of the main loop and before_terminate callback (damon_sysfs_before_terminate() in this case) is not yet called. And damon_sysfs_handle_cmd() can further be finished before the callback is invoked. Then, damon_sysfs_before_terminate() unlocks damon_sysfs_lock, which is not locked by anyone. This happens because the callback function assumes damon_sysfs_cmd_request_callback() should be called before it. Check if the assumption was true before doing the unlock, to avoid this problem. Link: https://lkml.kernel.org/r/20231007200432.3110-1-sj@kernel.org Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command") Signed-off-by: SeongJae Park Cc: [6.2.x] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/damon/sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1202,6 +1202,8 @@ static int damon_sysfs_set_targets(struc return 0; } +static bool damon_sysfs_schemes_regions_updating; + static void damon_sysfs_before_terminate(struct damon_ctx *ctx) { struct damon_target *t, *next; @@ -1209,10 +1211,12 @@ static void damon_sysfs_before_terminate /* damon_sysfs_schemes_update_regions_stop() might not yet called */ kdamond = damon_sysfs_cmd_request.kdamond; - if (kdamond && damon_sysfs_cmd_request.cmd == + if (kdamond && (damon_sysfs_cmd_request.cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS && + damon_sysfs_schemes_regions_updating) && ctx == kdamond->damon_ctx) { damon_sysfs_schemes_update_regions_stop(ctx); + damon_sysfs_schemes_regions_updating = false; mutex_unlock(&damon_sysfs_lock); } @@ -1331,7 +1335,6 @@ static int damon_sysfs_commit_input(stru static int damon_sysfs_cmd_request_callback(struct damon_ctx *c) { struct damon_sysfs_kdamond *kdamond; - static bool damon_sysfs_schemes_regions_updating; int err = 0; /* avoid deadlock due to concurrent state_store('off') */