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 6D340CD37B0 for ; Mon, 18 Sep 2023 05:34:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239685AbjIRFd7 (ORCPT ); Mon, 18 Sep 2023 01:33:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239604AbjIRFd2 (ORCPT ); Mon, 18 Sep 2023 01:33:28 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D0869F; Sun, 17 Sep 2023 22:33:23 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 431A9C433C7; Mon, 18 Sep 2023 05:33:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695015203; bh=ZSre9xUXaczWj7SY0m81+m7rnmYcDRo0030/fgV5cdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TANfFm6fmw4upz/D15/HMmKIdtp3e7oAQqqcn8BfeWoarFhn/LkGWZVe+7snKEyFU cOWWysL8c5SUUGGBnUIv6wmbUULwwtOE9dbAhECEdk8AgmsmnZpToArMXwUdcU8DRc 9gVFthnkt2IsWTRE+5XfZH07iVZwe00q3psZPuZC90fCEuabqwzaoTbk5ZxSPlnmQD cyV1Sg+jseVykrqA0XgXx81JSvKC4wGScf93+qIjP1sFgYQtvQlz7+NPbpwLaZ/qrL mjsCOeFWu1w4nnP5tNhQg3LKe801Xg0lJE/BSCrgLPBhx2MBDiJKx7MFSR+jUj2hhG s2g4KjcNWRBVw== From: SeongJae Park To: Jinjie Ruan Cc: sj@kernel.org, akpm@linux-foundation.org, brendan.higgins@linux.dev, feng.tang@intel.com, damon@lists.linux.dev, linux-mm@kvack.org, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND 1/2] mm/damon/core-test: Fix memory leak in damon_new_region() Date: Mon, 18 Sep 2023 05:33:20 +0000 Message-Id: <20230918053320.61408-1-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230918051044.3814018-2-ruanjinjie@huawei.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jinjie, Thank you for this patchset! On Mon, 18 Sep 2023 13:10:43 +0800 Jinjie Ruan wrote: > The damon_region which is allocated by kmem_cache_alloc() in > damon_new_region() in damon_test_regions() and > damon_test_update_monitoring_result() are not freed and it causes below > memory leak. So use damon_free_region() to free it. > > unreferenced object 0xffff2b49c3edc000 (size 56): > comm "kunit_try_catch", pid 338, jiffies 4294895280 (age 557.084s) > hex dump (first 32 bytes): > 01 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 49 2b ff ff ............I+.. > backtrace: > [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368 > [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284 > [<000000008603f022>] damon_new_region+0x28/0x54 > [<00000000a3b8c64e>] damon_test_regions+0x38/0x270 > [<00000000559c4801>] kunit_try_run_case+0x50/0xac > [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c > [<000000003c3e9211>] kthread+0x124/0x130 > [<0000000028f85bdd>] ret_from_fork+0x10/0x20 > unreferenced object 0xffff2b49c5b20000 (size 56): > comm "kunit_try_catch", pid 354, jiffies 4294895304 (age 556.988s) > hex dump (first 32 bytes): > 03 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 96 00 00 00 49 2b ff ff ............I+.. > backtrace: > [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368 > [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284 > [<000000008603f022>] damon_new_region+0x28/0x54 > [<00000000ca019f80>] damon_test_update_monitoring_result+0x18/0x34 > [<00000000559c4801>] kunit_try_run_case+0x50/0xac > [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c > [<000000003c3e9211>] kthread+0x124/0x130 > [<0000000028f85bdd>] ret_from_fork+0x10/0x20 Nice finding! Could you please share just a brief more detail about above cool output, e.g., just the name of the tool you used, so that others can learn it from your awesome commit message? > > Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") > Fixes: f4c978b6594b ("mm/damon/core-test: add a test for damon_update_monitoring_results()") > Signed-off-by: Jinjie Ruan > --- > mm/damon/core-test.h | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h > index 6cc8b245586d..255f8c925c00 100644 > --- a/mm/damon/core-test.h > +++ b/mm/damon/core-test.h > @@ -34,6 +34,7 @@ static void damon_test_regions(struct kunit *test) > KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t)); > > damon_free_target(t); > + damon_free_region(r); There is damon_destroy_region() function, which simply calls damon_del_region() and damon_free_region(). Unless there is needs to access the region before removing from the region, doing memory return together via the function is recommended. And this test code calls damon_del_region() just beofre above KUNIT_EXPECT_EQ(). Hence, I think replacing the damon_del_region() call with damon_destroy_region() rather than calling damon_free_region() may be simpler and shorter. Could you please do so? > } > > static unsigned int nr_damon_targets(struct damon_ctx *ctx) > @@ -316,6 +317,8 @@ static void damon_test_update_monitoring_result(struct kunit *test) > damon_update_monitoring_result(r, &old_attrs, &new_attrs); > KUNIT_EXPECT_EQ(test, r->nr_accesses, 150); > KUNIT_EXPECT_EQ(test, r->age, 20); > + > + damon_free_region(r); This looks nice. Thank you for fixing this! > } > > static void damon_test_set_attrs(struct kunit *test) > -- > 2.34.1 > Thanks, SJ