From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE7E15235 for ; Sat, 7 Oct 2023 20:04:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jblyM3cE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C135EC433C7; Sat, 7 Oct 2023 20:04:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696709077; bh=k+E7o4trRwpUVpsgiWw9zd/8lmV+kOwn1CHhDi4J/Yo=; h=From:To:Cc:Subject:Date:From; b=jblyM3cEtrib/74xHI17sH3ZJytEYYeAjCDJPFD3KBCStlKs9wJ2HGxDFdvarbqFx P36i22ZGZM67vyqEdfO9Ad3jx1oaK//GGZA5uBXorrNyJvqkq5qnAKDP3V+ZaLnAh2 lnmDVYg1qVN84i7cblbu/rhsRCro+/X6M3LTbksmIv1zXohwfC6C2WMYnKpP5LF3nw VMkFPEsWGWpg5KxdeWJFzPh8lQX0cgNxP7+f1bOspOyGrTM+fU2vkjw3ycEjAq5AIE O7yLzUTUHvd33/7pklmbQ53JP1Ni2pVLHSs0yw0YoLHOV0pPcH2ij2q6ez5KgWvQWF JrOsensvDSjTg== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/1] mm/damon/sysfs: check DAMOS regions update progress from before_terminate() Date: Sat, 7 Oct 2023 20:04:32 +0000 Message-Id: <20231007200432.3110-1-sj@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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. Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command") Cc: # 6.2.x Signed-off-by: SeongJae Park --- mm/damon/sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index b86ba7b0a921..f60e56150feb 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1208,6 +1208,8 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx, return 0; } +static bool damon_sysfs_schemes_regions_updating; + static void damon_sysfs_before_terminate(struct damon_ctx *ctx) { struct damon_target *t, *next; @@ -1219,8 +1221,10 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx) cmd = damon_sysfs_cmd_request.cmd; if (kdamond && ctx == kdamond->damon_ctx && (cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS || - cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES)) { + cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES) && + damon_sysfs_schemes_regions_updating) { damon_sysfs_schemes_update_regions_stop(ctx); + damon_sysfs_schemes_regions_updating = false; mutex_unlock(&damon_sysfs_lock); } @@ -1340,7 +1344,6 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond) static int damon_sysfs_cmd_request_callback(struct damon_ctx *c) { struct damon_sysfs_kdamond *kdamond; - static bool damon_sysfs_schemes_regions_updating; bool total_bytes_only = false; int err = 0; -- 2.34.1