From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 0BC833A0B0C for ; Tue, 24 Feb 2026 15:10:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771945841; cv=none; b=QJXEuEBmju5z9K7gdzG9ha5C2aVn2uJfEeHAWXUsds66LNEnaxGbk7/z9sgnSR/XI/3CLgOuHaw+rlFWUzTDOP1+eubk1pKcj5H3wUkHL7hr2zMlMDlNbXDdrihG3siAumcIThsOfTsvWS/JXoQyrBwInZDgtO65leLlyS0T62g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771945841; c=relaxed/simple; bh=BSd3E9HvM832bf2kO/myULtnTWMJZqXPY/uCr6QDO2g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QrH6Zpl/wsu30YCYb76jMpxBCD1YyDEeDPbYZ1cjJQvpHGl9KBNqVSM9DW3uIBsR4WwBtG8DEM46tA/18hesc0sjXWDnx4XdYTUwNpoHxUZaytZk1RXL8kSi1V0KIOkGbm6mn21dCliD6YDUSrw3S59h0Mw+u9RRYTIdF6+rN4k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=H8BZBiEA; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=Ctx/NHPY; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="H8BZBiEA"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ctx/NHPY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1771945838; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BSd3E9HvM832bf2kO/myULtnTWMJZqXPY/uCr6QDO2g=; b=H8BZBiEAK/gaF4kW89vzvCvJwvv5kjeLfj4rs7Lsg7KMZIGSFZDbx+7T3MikezmaHsyHjV 0fSZUOcvTyfKltIrzPgrm1uGJb1140gl2DO5ZK7vP4xSCgrpygTDxoIQnHMd8bjmtQCCWr 4p9XSGfOaN8wf3tptK7V1iO7pFvK4OI= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-678-Ns3_jHIrMeuI6U2r3P3FFQ-1; Tue, 24 Feb 2026 10:10:36 -0500 X-MC-Unique: Ns3_jHIrMeuI6U2r3P3FFQ-1 X-Mimecast-MFC-AGG-ID: Ns3_jHIrMeuI6U2r3P3FFQ_1771945835 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-48378df3469so40176155e9.1 for ; Tue, 24 Feb 2026 07:10:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1771945835; x=1772550635; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=BSd3E9HvM832bf2kO/myULtnTWMJZqXPY/uCr6QDO2g=; b=Ctx/NHPYh/VlIhSL+ainpWSuiJKnfGC3Usql9ihCvxFiUp2vlmta+HpKLeDjm3AI/w fOgG0S/LDwYrkqy2mOAODcmzvgS3YJwb+NLg3KFKE5b37Mui7bekLVT7aIq7MV9wT3X5 6IBPf2e1Bz72DRpBqb30IZweq1lDFj/Tg/HFUMp70asxmsNcszkQTpyp25yGs1qFw0D+ kjyPZkTd3sXijGeXIMOOL8PxAV4Ta4CuTcKxQZUuOaTqNfeM8Pl44eFRnZArqycjzIqx NrBxURzteGK9i2yZ1L21G7GciE+EQ2cVH4NBTIabyQzCjX/IsNkyE44zGtF78ryIE0b+ cL2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771945835; x=1772550635; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=BSd3E9HvM832bf2kO/myULtnTWMJZqXPY/uCr6QDO2g=; b=e22kM18G1ogvPVl8w6scypfxkZJoyUXiVis7UaRRkRsOQYqvyzZV3QrM4Mf05/0GZi evvWHE9pW0BfDkVadMcGsZlfT49VYlE6a5dXDfLXipL65HH1pIc39fC+hbY4D3oTLXjC 7OEgByX/VIHFVDvzq9Qhd53HFZdpI7Pi5Zc47X/iaDbNRVbhTHn1WI0OJ9zq8EWkmpca Bki6D5lTV5qt1b2W4JROUWApVNnFMai3iVc94f496T8h7vbYHshY11PyJoW7CZbmpUNa MtdxttR2PkLmnh3aBPz1JcR8tCnGmJc2O43Z11OcR0NYhZ1bzHKuJe+n9haa2xI5+sdi o84w== X-Forwarded-Encrypted: i=1; AJvYcCUR0MCk3lJiaq+UY1grc19AkgvniUA68TAOymGBaaWpQydf7SuI63hZa/pSsDmHz823g42VL7sa3N1FRVMlUl0=@vger.kernel.org X-Gm-Message-State: AOJu0YwD8fAC4a7bTtfOvz5nTdoaVbTCDhFBUsTLYcqqGOLxc3yBvtye EIv0kLJvYPs3k/cQFmauFHO14c2Bjj/npBffHUQ5CheORm+hUefV9F+6wuB0wyz3RukBCYbUTN5 3Qx+ncUHoZB+BvRygmBP/5NGYP+nMqJi5iADhPCv66AMOyxG7bGdBT/5pM1zQYpYIYFRs1A== X-Gm-Gg: AZuq6aJkKzJ9YMVGIdW65PM9w+/yWYpDYR3JP/gPhlrNmDw5M+XBR675S0Q/I5bNgBc PMVzrT24IU4AZJ4Bic4bO5hgCyEFawKiRBYaHjlgpfwtJlreRZvRNMtLstlVYt9pprzYAJ6a9QU L1kOlyk6ru8nvvhGBGaIJAqM6YaYvJ0YG8MVvGDKEw2lPGjuSqVoyjYWI6LVwylz3gce16twPpJ 6Vhb6ZMhedpH7+W1d+OYieXZ5Qfi853/BfdkDy/S4NMvqtynKmqYFAT0/1wHfQ24xttNHcBIl6n GDxCl4AXx8LPqEhKs20AbccXw7KQgOZuu60hzzLXb40ptbtCHq25VDjIaWey4wGjXJDdXp6G53y phqvzWUvBXokXdvxw+AAfppRW+k5BQYID6scm7XXdwy6ob8iSJhEtLHpbvzSQKDesU7H07Pw= X-Received: by 2002:a05:600c:c113:b0:483:4b37:8620 with SMTP id 5b1f17b1804b1-483bd742cddmr3686725e9.10.1771945835277; Tue, 24 Feb 2026 07:10:35 -0800 (PST) X-Received: by 2002:a05:600c:c113:b0:483:4b37:8620 with SMTP id 5b1f17b1804b1-483bd742cddmr3686325e9.10.1771945834815; Tue, 24 Feb 2026 07:10:34 -0800 (PST) Received: from sgarzare-redhat (host-82-53-134-58.retail.telecomitalia.it. [82.53.134.58]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-483b8791a0esm73910215e9.0.2026.02.24.07.10.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Feb 2026 07:10:34 -0800 (PST) Date: Tue, 24 Feb 2026 16:10:31 +0100 From: Stefano Garzarella To: Bobby Eshleman Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Stefan Hajnoczi , Shuah Khan , Bobby Eshleman , "Michael S. Tsirkin" , Jonathan Corbet , Shuah Khan , virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, kuniyu@google.com, ncardwell@google.com, Daan De Meyer Subject: Re: [PATCH net v3 2/3] vsock: lock down child_ns_mode as write-once Message-ID: References: <20260223-vsock-ns-write-once-v3-0-c0cde6959923@meta.com> <20260223-vsock-ns-write-once-v3-2-c0cde6959923@meta.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Mon, Feb 23, 2026 at 04:24:07PM -0800, Bobby Eshleman wrote: >On Mon, Feb 23, 2026 at 02:38:33PM -0800, Bobby Eshleman wrote: >> From: Bobby Eshleman >> >> Two administrator processes may race when setting child_ns_mode as one >> process sets child_ns_mode to "local" and then creates a namespace, but >> another process changes child_ns_mode to "global" between the write and >> the namespace creation. The first process ends up with a namespace in >> "global" mode instead of "local". While this can be detected after the >> fact by reading ns_mode and retrying, it is fragile and error-prone. >> >> Make child_ns_mode write-once so that a namespace manager can set it >> once and be sure it won't change. Writing a different value after the >> first write returns -EBUSY. This applies to all namespaces, including >> init_net, where an init process can write "local" to lock all future >> namespaces into local mode. >> >> Fixes: eafb64f40ca4 ("vsock: add netns to vsock core") >> Suggested-by: Daan De Meyer >> Suggested-by: Stefano Garzarella >> Co-developed-by: Stefano Garzarella >> Signed-off-by: Stefano Garzarella > >Stefano, I wasn't sure if you wanted the Co-developed-by and S-o-b on >this iteration, but I added it just in case. Please let me know, if that >wasn't what you intended. It's fine, thanks for that! Stefano