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 B5F6E3C4572; Mon, 1 Jun 2026 13:57:41 +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=1780322262; cv=none; b=oLSbzOFQxh/Li+TWMZRDekMZpMOX4GqFAJfdhMpVoCKSHextZkfjRe7AZlt+Yelp2aHaulp8YY1zbt2FAfST9gxkUaYsN6fNpBbQsTNL7iT/dgeeFJSad4jpYGxTlkKVhNF/c7sFTc2uUSsIoFgTarqd3Nc3TGbhgTWrmmb89/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780322262; c=relaxed/simple; bh=z7GBo2weiXPtLaPB9BVPXUk8vJr3dGQnDTEHCR8NQ6U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Rm7jppO1KaBTW2QixHzZGPAN8Tr/tVCwCMzfe5JbDFsxJtUWgYHGCbn4+xMH8JWZtv5SKsu5Apb/WAdu5wG8Z7chXOu73fXhgb9kN4yGy2+iSCNU6xpcYaHg6PI3rMJB0b/Xo/yn8EyklIO5LqYTKvCBk7zzMFPv/jX4V60Fn3o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VpHNy3ZG; 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="VpHNy3ZG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF0211F00899; Mon, 1 Jun 2026 13:57:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780322261; bh=Nmf3Ti8FB/Rw0EAEp2RpoYeHAFdBinkz4dUeZgaGrCU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=VpHNy3ZGPI0gap5s12INMmIn25fJZczX8We3UHZ7D6u9hutISGSVnMNd88Mv7WS+c pbIMELKWoOfA4vS7fJUYFWPxRzyzXhQ6e3yt4VyrAKelvalJ04jIKIgTkN5VNyuJM0 qUvILzY/1qKAZ6CFrfQd+T6Ld6vuQvR/J8L1sM9uwGVlRjDl4FIeeA1zwx4dYTmBgl auejHFGENLBGol+2nhH/oANKIpi3QLhl9GXtfqa0SVtQ3+6BeW9eTHts5xkXw6aqZk dALmq5rlHMI+Sx7HjOcPVulpnZmBM8iFCMoDiMYGl3x5nFUGW1NkPKH9y1zqu1Zc3q XJrSmGEFVqDJA== From: Christian Brauner Date: Mon, 01 Jun 2026 15:56:54 +0200 Subject: [PATCH RFC v4 21/25] devtmpfs: create private mount namespace Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260601-work-kthread-nullfs-v4-21-77ee053060e0@kernel.org> References: <20260601-work-kthread-nullfs-v4-0-77ee053060e0@kernel.org> In-Reply-To: <20260601-work-kthread-nullfs-v4-0-77ee053060e0@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara , Jann Horn , "Christian Brauner (Amutable)" X-Mailer: b4 0.16-dev-fffa9 X-Developer-Signature: v=1; a=openpgp-sha256; l=899; i=brauner@kernel.org; h=from:subject:message-id; bh=z7GBo2weiXPtLaPB9BVPXUk8vJr3dGQnDTEHCR8NQ6U=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWTJ9i/fGm8yv551d8viJuXyFYpf8hqtl/0SPfu79Ynr9 pV+bKwvO0pZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACaSU8zwP2FuU6LhG7kaH+/m HS5rXt9hE/6qxlVvVnjt9qxU1cy+ZEaGk4rsi2uYZhU+zVNb9HuByAr32L8Lvj38Jf3lteMEycX HOAA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Kernel threads start in a completely isolated nullfs mount. Use UNSHARE_EMPTY_MNTNS to give the devtmpfsd kthread a private empty mount namespace with its root and pwd already set up, so it can mount its own devtmpfs instance instead of unsharing a copy of the initial mount namespace. Signed-off-by: Christian Brauner (Amutable) --- drivers/base/devtmpfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index b1c4ceb65026..aef0fcc6aba1 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -413,7 +413,7 @@ static noinline int __init devtmpfs_setup(void *p) { int err; - err = ksys_unshare(CLONE_NEWNS); + err = ksys_unshare(UNSHARE_EMPTY_MNTNS); if (err) goto out; err = init_mount("devtmpfs", "/", "devtmpfs", DEVTMPFS_MFLAGS, NULL); -- 2.47.3