From nobody Tue Apr 7 21:23:56 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C88CB37417C; Wed, 11 Mar 2026 21:57:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773266225; cv=none; b=qjtiYd8uTrkv+ynas5lbzkTOOeKouKlw1hwGpOwBs47gV/UB3qniZcL7LHb1a2Oha4IJKN0xjYbzZ6kUJOOtYMthnuyoLhfTeq+I2vP56ecV8bupxGgQYBcKQWprQHcazMpYawuGqDH+d7siz9iXLlJpkJTLdS/ZR3hm1XSIm68= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773266225; c=relaxed/simple; bh=LEkYCP2B26VM04U/Xfgf30JgLqLChdLWXV57GkA2dNs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OKuTEJ8lHnLwE2g+Sam6IuokufWD5TiQvroOdL2DliOvGInpD13zCBMebC7ihserlFCvT51sIVeumqfFEOTkkIRj+YxZMEaUwO0NeMHtEXazBf8hxCHTLI1tTO8drJ1HqbtUJB6dOwVVVk5v8SbEGS+xly4K3kzZDrfa5Dl/RKA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AKzPHBAT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AKzPHBAT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6D73C4CEF7; Wed, 11 Mar 2026 21:57:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773266225; bh=LEkYCP2B26VM04U/Xfgf30JgLqLChdLWXV57GkA2dNs=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=AKzPHBATsS/mL4PJnheBXkgfMRwEVUBgU9XYFk2v+qqiFhskqcja0yivodaLiIzvD ZkWBwICPGmTxMtSkDcBOu46t+XeyWK5fZss6w3o8Zk8Gzz0sVbRhNz5omx14WkdRTg Ig4nyleH/C0Hv8/OFJwfuTBPxJtNOa6KHjCsMEayRkbqW4IIthKRi+2ajVPwmYnru7 8oqGqXoEzCaIbJFGhSi2Pl4S4nSRv07nQd/ochmmwU9MvDrdl4fMtSanNTYRs6frZD dUo1KBLnymW1sM03Ilw3bMEMciT9RlxJcCEMmrPPs+IhIohIK9x/iBhqf5nW2r2TgX jkJGdNixFXa1g== From: Christian Brauner Date: Wed, 11 Mar 2026 22:44:05 +0100 Subject: [PATCH RFC v3 22/26] 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: quoted-printable Message-Id: <20260311-work-kthread-nullfs-v3-22-3dd2cbe92ad0@kernel.org> References: <20260311-work-kthread-nullfs-v3-0-3dd2cbe92ad0@kernel.org> In-Reply-To: <20260311-work-kthread-nullfs-v3-0-3dd2cbe92ad0@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Alexander Viro , Jens Axboe , Jan Kara , Tejun Heo , Jann Horn , Christian Brauner X-Mailer: b4 0.15-dev-9fd7c X-Developer-Signature: v=1; a=openpgp-sha256; l=792; i=brauner@kernel.org; h=from:subject:message-id; bh=LEkYCP2B26VM04U/Xfgf30JgLqLChdLWXV57GkA2dNs=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRufPJTScfwXeA+tmr5OFctjcr4hq73h9wuZTz5rT9pz fbcJsbVHSUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABN5v5Dhe4bra/3P3wJ/HXzE d2KHctCdCS+2PTdya5w+SaMy/PoDVoZ/Rn0xQbMydT+xXj5vGXm31aDOqpVr+QGdNKcwA3WlPiE GAA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Kernel threads are located in a completely isolated nullfs mount. Make it possible for a kthread to create a private mount namespace so it can mount private filesystem instances. This is only used by devtmpfs. Signed-off-by: Christian Brauner --- 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..246ac0b331fe 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; =20 - err =3D ksys_unshare(CLONE_NEWNS); + err =3D kthread_mntns(); if (err) goto out; err =3D init_mount("devtmpfs", "/", "devtmpfs", DEVTMPFS_MFLAGS, NULL); --=20 2.47.3