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 4A0151EF0A3 for ; Wed, 2 Apr 2025 23:24:29 +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=1743636270; cv=none; b=gIobWXF2U87fET4p+jZzcveH4PTWEhtulgl/MxXvhf9xkAwCfJF5gsQrN27Yp2T82sExLNc0txnrPAC3jPj8B02yFXanR+1LWvMCobaVqBgHj4oJvRUiiSnVaoPvLTzfm4rFsSh3T0NtNzEQPSH0ngfgGorZ7z/daSuVSHC5mXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743636270; c=relaxed/simple; bh=ItVDTJdNiw8uaHk9iV1rg5Ps7P/YyhnkysOK88V2Xkc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=I6jJYzp3PEwA5rrtNoUuBuDbrvTFNf5A8jTjuoqFE3Zsc0Mwdmq7cmnFBXF+zpf4n2fnAyamcmi0KvDiKthFVSlD46Jtae+B4hdyBEPv2eXHy1nyFUNNTGoJzNrJ9JCfeCfGzfFBy9PEmDObz+bS1o5ksbCXylB2uPkAI54qyWE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Wmisjzy+; 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="Wmisjzy+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55E70C4CEDD; Wed, 2 Apr 2025 23:24:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743636269; bh=ItVDTJdNiw8uaHk9iV1rg5Ps7P/YyhnkysOK88V2Xkc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Wmisjzy+Cjy+0/xHWlvRmtl+ZLL/mI/bL3ST1r8KYql5/RPb5bg1RKteRJBneMrSa qQPESIakYdsFgZLWgkL/eTLJXkS+lBMoNz8sqrlY4x4EbU06UvPIwrO+XCQnIsdVi4 j4B3lyKMj6gqT/OHgxf4mQV2hTlERQeezZ/HVFYSan49VIlWS95DfikJyde8To0IRi Hpa2ooliMCQG3b3AY4npbJfDSND+5X9S9qV0Zy86j55H347rCwDdY53tg0QaZB1G4u 3UP9zBIaSs2AKF67TEdhErz8xPXRpePnVUhxwpzER4o/mOD5VcWEutERY2x0FOOQ8W 8S0xdC0xs4F/Q== Date: Wed, 2 Apr 2025 16:24:28 -0700 From: Jakub Kicinski To: Mina Almasry , sdf@fomichev.me Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, ap420073@gmail.com, asml.silence@gmail.com, dw@davidwei.uk Subject: Re: [PATCH net 2/2] net: avoid false positive warnings in __net_mp_close_rxq() Message-ID: <20250402162428.4afc90cb@kernel.org> In-Reply-To: References: <20250331194201.2026422-1-kuba@kernel.org> <20250331194308.2026940-1-kuba@kernel.org> 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 Wed, 2 Apr 2025 11:52:50 -0700 Mina Almasry wrote: > > netdev_lock(dev); > > - __net_mp_close_rxq(dev, ifq_idx, old_p); > > + /* Callers holding a netdev ref may get here after we already > > + * went thru shutdown via dev_memory_provider_uninstall(). > > + */ > > + if (dev->reg_state <= NETREG_REGISTERED) > > + __net_mp_close_rxq(dev, ifq_idx, old_p); > > Not obvious to me why this check was moved. Do you expect to call > __net_mp_close_rxq on an unregistered netdev and expect it to succeed > in io_uring binding or something? Yes, iouring state is under spin lock it can't call in here atomically. device unregister may race with iouring shutdown. Now that I look at it I think we need diff --git a/net/core/dev.c b/net/core/dev.c index be17e0660144..0a70080a1209 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -11947,6 +11947,7 @@ void unregister_netdevice_many_notify(struct list_head *head, unlist_netdevice(dev); netdev_lock(dev); WRITE_ONCE(dev->reg_state, NETREG_UNREGISTERING); + dev_memory_provider_uninstall(dev); netdev_unlock(dev); } flush_all_backlogs(); @@ -11961,7 +11962,6 @@ void unregister_netdevice_many_notify(struct list_head *head, dev_tcx_uninstall(dev); netdev_lock_ops(dev); dev_xdp_uninstall(dev); - dev_memory_provider_uninstall(dev); netdev_unlock_ops(dev); bpf_dev_bound_netdev_unregister(dev); since 1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") we drop the lock after setting UNREGISTERING so we may call .uninstall after iouring torn down its side. Right, Stan?