From nobody Mon Feb 9 23:00:50 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 DDC9A1DF276; Tue, 28 Jan 2025 08:42:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738053760; cv=none; b=gpyW3TbTOnkX8LP5l4rt8osOol7e69F1v0SRAktE2OAs9OTBEsj7rPpv4INlbGfU86bz9V7LdqUPBL0Nr41jyIc8YrITPVOExqIIaHbnEHSWlGqH8WwTNQffKCYccOpNSNmDlmal2hs0wZnjW/DM/sndH02I895Phhu/KiBX6aA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738053760; c=relaxed/simple; bh=+kwU2zFUMmyb0jS6OU6MFBxnBiiwKa4vGC/wQUaUfq4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tj+VAz15gVq7D0vqWnYP2ogHARqzhu1KlovyRbrHhhAnwj0clN+G96Vcm9JKlXUna1Oqvqyib2AEyDjLCl+Nx1cHnQnIB4Oqan3jxHLKKjy8q7jePZ1jkGpOs3PGEm0j6SDC7tYbVPReklQ0Mga0h+svF/S/JuR4TD8Ga0wKKoc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=ewSz62oL; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Px56zWbN; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="ewSz62oL"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Px56zWbN" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1738053757; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TQFaRwsMWqeRZCHTYyBsT4gxYaSSc81PYJjjcc6W9Sk=; b=ewSz62oLj2/KMFS48hv7Y0XNGe0UJ6XG1CNtyxntwmZk7fYcMPj09tAbLZx0w460/mol9p RXuvG1C+BZhMc/xgevFnD9yRwI/m+vGZl/A2J2eIst9Tj/eiAYjgbjRyylonZyqQ1v9Yof XPn86EsWFfmyJNfbvuPS0+oZEW88xt6JKUA3oGQuxaECzXFDi/oarS57jw4Z8wo4uN4v4h QZSxjbSKawahhqQc4j//2dh77n0Rf3No9rWY/EScWa49o6zG/5gq780RS7iH+eN4zTWL7V zvJSZQxDhtx4A3Qpd3FVP0Q6+HgqjSBBse+hwMO2DE5SAUuRpqbQTGEnGCAR1A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1738053757; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TQFaRwsMWqeRZCHTYyBsT4gxYaSSc81PYJjjcc6W9Sk=; b=Px56zWbNjSZ0+OYjnW/jj4xKl9YoAVAYBr92oMtITr2Alv32/CjA/Pyjmvg35uKTlJBLWB 866Sgjwpe6JOT6CA== To: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Michal=20Koutn=C3=BD?= , "Paul E. McKenney" , Boqun Feng , Greg Kroah-Hartman , Hillf Danton , Johannes Weiner , Marco Elver , Tejun Heo , tglx@linutronix.de, Sebastian Andrzej Siewior Subject: [PATCH v5 3/6] kernfs: Acquire kernfs_rwsem in kernfs_node_dentry(). Date: Tue, 28 Jan 2025 09:42:23 +0100 Message-ID: <20250128084226.1499291-4-bigeasy@linutronix.de> In-Reply-To: <20250128084226.1499291-1-bigeasy@linutronix.de> References: <20250128084226.1499291-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kernfs_node_dentry() passes kernfs_node::name to lookup_positive_unlocked(). Acquire kernfs_root::kernfs_rwsem to ensure the node is not renamed during the operation. Acked-by: Tejun Heo Signed-off-by: Sebastian Andrzej Siewior --- fs/kernfs/mount.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index b9b16e97bff18..4a0ff08d589ca 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -209,6 +209,7 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *k= n, { struct dentry *dentry; struct kernfs_node *knparent; + struct kernfs_root *root; =20 BUG_ON(sb->s_op !=3D &kernfs_sops); =20 @@ -218,6 +219,9 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *k= n, if (!kn->parent) return dentry; =20 + root =3D kernfs_root(kn); + guard(rwsem_read)(&root->kernfs_rwsem); + knparent =3D find_next_ancestor(kn, NULL); if (WARN_ON(!knparent)) { dput(dentry); --=20 2.47.2