From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2FCC14418DF for ; Tue, 16 Jun 2026 15:25:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623555; cv=none; b=FvQ8AzYM7NnoMsA3MB95byK8+IDEuAO44FYgmKUPOJAVCRSuDfa/zp8FX1ZkYLDF4qHjUoQoawFO0WsgdFMzePGlktpnsyIVyIO2dWa8NLlGI16xc+vm6YajHLC3mw4Mv3VfU/tecKpvH61wOJl1enfkVyT3qLoGfGKQkAuBOc4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623555; c=relaxed/simple; bh=qva4pTL4LZq9a7ReG18dZGabCax8WLpUfmHFw4DeOrs=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=UIrZ8dQw6pA5+0AZ7tRNJ6nbiNe5Q6qv0JK4nqxjUDzd4G+cB3/EbTxiSjLv0Tp+YJGiwdfwxRIzuRRMznhIemMltjfwtgAcgSq6mY2xvi0Rhai96V1vfzupH0BSKdVaxmYAAIGH7ciKb9dpO442Qw/GWCSvS0JWcG9im+Qo1Fg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B78LDo+E; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B78LDo+E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C97A01F000E9; Tue, 16 Jun 2026 15:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781623554; bh=eJvppLPhCZq9hhCtcsWxprxEHwFh/no53pHEomtsI3M=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=B78LDo+EasZCAqYem93+vuMSX7Noqe9I9kQhJeLIIt5fyEf0srzXZO5oDWBn+meEE YGiONqOAt8Fq7KjLjaQKNMALNxpibQDEj2MslcFvhfj9ZUIXSvTXIyyUAXRVny93op yTpve/xohX4TObeu06JfEvCz9scBi5xWlJ0WphN1Qp52G5q/U5i62ILE9PbBxYR1JH VmN9gPbyGt73cjciVpYD8JRgIdPpAn81xQ8VqCw3OYRhVMTrSVaH+F6cUDSUe1oA+i TSAUkaZbc0nCPHaiEC9+peHAJppRJHgVRW1tZcjRjPypsokSwrmXvb/QyFI49H9DEk CR4lS3OkGlkww== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH 1/9] mm/damon/sysfs: kobject_del() target, context and kdamond dirs Reply-To: sashiko-reviews@lists.linux.dev To: "SeongJae Park" Cc: damon@lists.linux.dev In-Reply-To: <20260616150844.88305-2-sj@kernel.org> References: <20260616150844.88305-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 16 Jun 2026 15:25:52 +0000 Message-Id: <20260616152553.C97A01F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: Pre-existing issues: - [High] Incomplete fix: Missing kobject_del() in sysfs directory creation = error paths leads to persistent -EEXIST collisions. -- commit 1c0329e17860c383f4ab90a119f917db75ecacee Author: SeongJae Park mm/damon/sysfs: kobject_del() target, context and kdamond dirs On CONFIG_DEBUG_KOBJECT_RELEASE enabled kernel, lack of kobject_del() could cause directories creation failures due to the name conflicts. Fix those issues for target, context and kdamond directories by adding kobject_del() calls. Fixes: c951cd3b8901 ("mm/damon: implement a minimal stub for sysfs-based DA= MON interface") Cc: # 5.18.x > diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c > index 2e95e3bac774d..d93f7919c3ca1 100644 > --- a/mm/damon/sysfs.c > +++ b/mm/damon/sysfs.c > @@ -333,6 +333,7 @@ static void damon_sysfs_targets_rm_dirs(struct damon_= sysfs_targets *targets) > =20 > for (i =3D 0; i < targets->nr; i++) { > damon_sysfs_target_rm_dirs(targets_arr[i]); > + kobject_del(&targets_arr[i]->kobj); [Severity: High] This isn't a regression introduced by this patch, but while you are fixing the -EEXIST name collisions in the rm_dirs() paths, are the same kobject_del() calls also needed in the error paths of the corresponding add_dirs() functions? For example, in damon_sysfs_targets_add_dirs(): mm/damon/sysfs.c:damon_sysfs_targets_add_dirs() { ... err =3D kobject_init_and_add(&target->kobj, ...); if (err) goto out; err =3D damon_sysfs_target_add_dirs(target); if (err) goto out; ... out: damon_sysfs_targets_rm_dirs(targets); kobject_put(&target->kobj); return err; } If damon_sysfs_target_add_dirs() fails, kobject_put() is called without kobject_del(). Does this result in a lingering directory and a persistent -EEXIST if the user retries? Similarly, in mm/damon/sysfs-schemes.c:damos_sysfs_populate_region_dir(): mm/damon/sysfs-schemes.c:damos_sysfs_populate_region_dir() { ... if (kobject_init_and_add(®ion->kobj, &damon_sysfs_scheme_region_ktype, &sysfs_regions->kobj, "%d", sysfs_regions->nr_regions)) goto out; if (damos_sysfs_region_add_dirs(region, ctx, r)) goto out; ... sysfs_regions->nr_regions++; return; out: kobject_put(®ion->kobj); } If this fails, it returns without incrementing sysfs_regions->nr_regions. Could the next region processed in the loop then attempt to initialize with the exact same name string, immediately hitting -EEXIST and breaking the entire region population loop? > kobject_put(&targets_arr[i]->kobj); > } > targets->nr =3D 0; [ ... ] --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260616150844.8830= 5-1-sj@kernel.org?part=3D1