From nobody Tue Feb 10 00:21:41 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 003DA205AB8; Mon, 3 Feb 2025 13:50:32 +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=1738590634; cv=none; b=kE/wiYZayUshmiHln0L6kG5rwWp3GcVcapBHvjUxGFdejkm4Qf8NMbFEhCK78SV7NukEJIaSVcM3L8pU2eWqHBntY/pIMojLx36z3mZk7UkgnN/B7jhqPu0Hmn2DqXwcd+wI/Hl0wBUUmcJRtyO0BlqkMSXnJ4oBnazOly1j8Ro= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738590634; c=relaxed/simple; bh=+kwU2zFUMmyb0jS6OU6MFBxnBiiwKa4vGC/wQUaUfq4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=M4r1Rkzp/pFsfbG+HBMd178HTCHauxvCsmo0UDED5F4VVA4Pwo3H1ILdPF0nyg66g8+aptL6zUD5VLUOPgDYukRO/dGi4jZkbs7BYicelSEMivTXivDYSfSnzdjPx85ue/8fv0UxWISVOV29UGqAMxkCgZ26uGqOihm5QC8CjQo= 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=erMmRs5S; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=EKLUqv5I; 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="erMmRs5S"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="EKLUqv5I" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1738590631; 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=erMmRs5S2OuceqmxziPo21AY0RG26sBi4tQDd4MjmM9aDZoUv/xH00CNhGqnsFWzNaMyh+ eoDhtpbngOtrMrfsxSuteJSIFTR9F9MzhbCvNqNSgg9VMmr12I7XEgt5N4vRo28TaXuPTx fei8KSX6UW3wiyNB3NyxC72Jqc3b//Iz1uG5pibYc6cZnsOzS07TdmuBD5D8cvfAU/lsrf 0oqtj5HhFXW6w139jDenNcII5qDVYU2XUaLwc5+PSxxO4A9W+fLzOeGJp6dLXklCc6PTwZ cUK7pvSwuZvgb590Uq2TikyCOaUH3b/Daqb+R+iEycJGE0HIPvfazafDOaNsVw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1738590631; 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=EKLUqv5IPKKAyj/vogMF4bfc8BN8k7swlaBVGlm36/1M2Qj59eCNAEb81sFxVXaGPg2i0U Lduwbf5UhTyv0IAA== 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 v7 3/6] kernfs: Acquire kernfs_rwsem in kernfs_node_dentry(). Date: Mon, 3 Feb 2025 14:50:20 +0100 Message-ID: <20250203135023.416828-4-bigeasy@linutronix.de> In-Reply-To: <20250203135023.416828-1-bigeasy@linutronix.de> References: <20250203135023.416828-1-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