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 D193926B970; Thu, 22 May 2025 22:13:48 +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=1747952028; cv=none; b=A+/v3Jf/REaegTvsegUzCLc7WEzxjhhe1jNW2iFI2GfEC4wlt2+GLtU4N53UQxuW9JfD9z7kdszeVbt6mkWrsx7wcfcRLDoR/Iu3NzMkY45n3OFkPjIujj1TxGTGeDetxSQzSSVAHYr62ISLGq3kj+GlCVCIqKkgbOPYJeQ9VGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747952028; c=relaxed/simple; bh=0gNOwm+ixznGLcCYt/xPhR3d4d4LaGz5vTfy/hu3DeU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TgVEYI/itjKn/xWlQLfQ2NpPy/b2sc5xUjeITaPHSmdNzbF/28wKO7M1iYPDxII5+FZHj1LcfzqrOjZGjwE4ZvNg7/hYSxltcMNMuMllY2yWtoabaAmRcLnsQ+NaxLKOfKVktCOkXdWx6wV2KQJWGuNGxEqdfnJ6+NdV37l8uKw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QayDC5Eg; 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="QayDC5Eg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAEE9C4CEF1; Thu, 22 May 2025 22:13:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747952028; bh=0gNOwm+ixznGLcCYt/xPhR3d4d4LaGz5vTfy/hu3DeU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QayDC5EgTGqTHm0LyhLO+93nYto8xwaXxnmHWOcLfK9JGJs5wwNjDt8zRihB8Bsaf WI0+IvnCEntuufcLV0Niu8z93wdydo3Lz1HcO7+x9qUBS7yFR9NMMhYoGnI0WF33Z4 Y2Okq3RJ/2dobr+h9w0/Y7z8G2WXPuv6s07o2aWzKNqx4zB2n6LgB8fhpKMm2v6fZZ zWF9jyp1KxIi+4qsjfrTZAGcDwrZhufzJO5ICENGEeK/NhKfUhjnu8+LFOK3sZFkdx 0PjqtGz4RitRwfzkVSqXwcSgUIwwzKjhcSxt1zmR3w8JEmGNyU7S2vdAy7cyCplqqo V6Gd3sU0/yn1g== Date: Thu, 22 May 2025 15:13:46 -0700 From: Jakub Kicinski To: Saurabh Sengar Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, kuniyu@amazon.com, ahmed.zaki@intel.com, aleksander.lobakin@intel.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, ssengar@microsoft.com, stable@vger.kernel.org Subject: Re: [PATCH net,v2] hv_netvsc: fix potential deadlock in netvsc_vf_setxdp() Message-ID: <20250522151346.57390f40@kernel.org> In-Reply-To: <1747823103-3420-1-git-send-email-ssengar@linux.microsoft.com> References: <1747823103-3420-1-git-send-email-ssengar@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-hyperv@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 Wed, 21 May 2025 03:25:03 -0700 Saurabh Sengar wrote: > The MANA driver's probe registers netdevice via the following call chain: > > mana_probe() > register_netdev() > register_netdevice() > > register_netdevice() calls notifier callback for netvsc driver, > holding the netdev mutex via netdev_lock_ops(). > > Further this netvsc notifier callback end up attempting to acquire the > same lock again in dev_xdp_propagate() leading to deadlock. > > netvsc_netdev_event() > netvsc_vf_setxdp() > dev_xdp_propagate() > > This deadlock was not observed so far because net_shaper_ops was never set, The lock is on the VF, I think you meant to say that no device you use in Azure is ops locked? There's also the call to netvsc_register_vf() on probe path, please fix or explain why it doesn't need locking in the commit message. -- pw-bot: cr