From mboxrd@z Thu Jan 1 00:00:00 1970 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 2DA1135977 for ; Wed, 19 Feb 2025 03:02:59 +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=1739934179; cv=none; b=qI9jzaBP7HQ9hspgotuXcXuRfcbXiDU6HmlU6NPUiz/s7MXp3WX7Oo2F1+LFlkYIN7Ofzaq8L2ahCbf503D/q7neN7EFJKJcSoV9P6L1jTvEdi+lVTMuuGQjJry7aLu90dFZiGP79pVpKSWmqdW7N2JL4IIuBS9euSEZOaTFfxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739934179; c=relaxed/simple; bh=RsmX1l+teidMolSiQ3jyBLMn4vFDbeN7Oja9uRjcKfQ=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=X22OyRVac9M93N5YxZ0pXMV6YZ0jMDKnwpmOJdvf87jnZQdN2rf6l9P5B42ddyYLYMAUrXyy/AypJbtB1heiACzB2kRgF0GSJEs1MJMTzYJkc7p5s93YKDqQabEvPIACxsjxwsJCnSoI/w5bxYtl2PU9nUBx9DbCpmnq2RvR/uo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aP+OTTMM; 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="aP+OTTMM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0A83C4CEE2; Wed, 19 Feb 2025 03:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739934179; bh=RsmX1l+teidMolSiQ3jyBLMn4vFDbeN7Oja9uRjcKfQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=aP+OTTMM+8x3XYo7ti9M6a7EvMFvrkO6JGW3wevGkqSkC6FI0UFB6mfOjdMez4+eM JNdJKuBnncK8BpImgqrtq7w9N0Kgy4O3+Tr5tMjesWYxk7+y3AQKy72YaZ6UR2l5/U MMMrOpxaNgwTKxM7O1W9tVw6xcOLHFsTIV6bvFVYfzBljUiAbQ3DvWhRb8jPSheauh viMVHFR2LEMpL/h9BFuqfEaM1MNR8+5aCa1CSV95LlkqP44IvvXA8EG3uCmwMgj1FB cOvyyE+gyQl6vWbhnmUdTi8hlT3Fli3NGicmhGl5hGFnF6kG2DQKEOf2sD7FtYdR9+ YfR8/j2/DWeAQ== Date: Tue, 18 Feb 2025 19:02:58 -0800 From: Jakub Kicinski To: Stanislav Fomichev Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, Saeed Mahameed Subject: Re: [PATCH net-next v4 07/12] net: hold netdev instance lock during ndo_bpf Message-ID: <20250218190258.5c82026b@kernel.org> In-Reply-To: <20250218020948.160643-8-sdf@fomichev.me> References: <20250218020948.160643-1-sdf@fomichev.me> <20250218020948.160643-8-sdf@fomichev.me> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 17 Feb 2025 18:09:43 -0800 Stanislav Fomichev wrote: > --- a/kernel/bpf/offload.c > +++ b/kernel/bpf/offload.c > @@ -528,10 +528,10 @@ struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) > return ERR_PTR(-ENOMEM); > > bpf_map_init_from_attr(&offmap->map, attr); > - > rtnl_lock(); > - down_write(&bpf_devs_lock); > offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); > + netdev_lock_ops(offmap->netdev); > + down_write(&bpf_devs_lock); > err = bpf_dev_offload_check(offmap->netdev); > if (err) > goto err_unlock; > @@ -548,12 +548,14 @@ struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) > > list_add_tail(&offmap->offloads, &ondev->maps); > up_write(&bpf_devs_lock); > + netdev_unlock_ops(offmap->netdev); > rtnl_unlock(); > > return &offmap->map; > > err_unlock: > up_write(&bpf_devs_lock); > + netdev_unlock_ops(offmap->netdev); > rtnl_unlock(); > bpf_map_area_free(offmap); > return ERR_PTR(err); Any reason for this lock ordering? My intuition would be from biggest to smallest, so rtnl_lock -> sem -> instance