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 55F3B3FD1 for ; Fri, 11 Apr 2025 02:23:27 +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=1744338208; cv=none; b=K7LEIaW/DN/G4gXmAGMXwNaTtByOANoM2VLrA2yWA702Bz016UoSkbxyX2mt9bmWKtInDEcVUErtDR+3SzwZ+bPLsWgDuca7dTNlT9YJ4Ub1e4+8kZf8zyx99h1rAbl/ZYd294bO8lbKMQKJMCCGLPpjlDFP171zqxjzgqCh6lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744338208; c=relaxed/simple; bh=/msYS6J0X9FKkpyR/dJxeB4OzJbVxqz0aa/Q8HBKnfE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FqhJg1YnIvpD6xvQhszxAVSXokdRnDsl3tPe7xVvuVFJp09Br2BhPSqCwP/dTTVO0EAboJ5bIkT3IQJOQJnfhorYfuYYgdCrHicS0GRKQoBvzr1P6hXFJYdb6jFyRCigMtbmHlsRukcqqthsI388yEXAZVYJabElPvdAv+4xOsQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QeEFXggT; 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="QeEFXggT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1ECDFC4CEDD; Fri, 11 Apr 2025 02:23:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744338207; bh=/msYS6J0X9FKkpyR/dJxeB4OzJbVxqz0aa/Q8HBKnfE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QeEFXggTzBjf2nNDTLm/7B/U5b0IVw9J/kBlXBy4+W4qQibF7unkccqHCly9xh2c/ jjRDok9Z+lgHAxMQ3McTAPlvIC5i7KOWa5JIew8tZBWzzWKvzRP81lt1Dpd0R2+dRB 0vKiFmFKnwpzgUioWxodPsdwAVJPx8ZdJzwvc3rAiaDnvwH2yIqdezAAjwogID7wuM +Z6Jb98zuI77JqPJzjUPOUwHTFLUFdaw2Yl+xqvZOT2UFF6nPQ6Y/PvfrSbLeXUtkd PZuz76PC+grpC4QJraQVrNJfjlNDlzPUskutfwu718DI8DCMkUYeKcyQTe9Mn05ceF WbsfIjTLtHwdQ== Date: Thu, 10 Apr 2025 19:23:26 -0700 From: Jakub Kicinski To: Cc: Kuniyuki Iwashima , , , , , , , , Subject: Re: [PATCH net-next v2 6/8] netdev: depend on netdev->lock for xdp features Message-ID: <20250410192326.0a5dbb10@kernel.org> In-Reply-To: <20250410191028.31a0eaf2@kernel.org> References: <20250408195956.412733-7-kuba@kernel.org> <20250410171019.62128-1-kuniyu@amazon.com> <20250410191028.31a0eaf2@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 Thu, 10 Apr 2025 19:10:28 -0700 Jakub Kicinski wrote: > On Thu, 10 Apr 2025 10:10:01 -0700 Kuniyuki Iwashima wrote: > > syzkaller reported splats in register_netdevice() and > > unregister_netdevice_many_notify(). > > > > In register_netdevice(), some devices cannot use > > netdev_assert_locked(). > > > > In unregister_netdevice_many_notify(), maybe we need to > > hold ops lock in UNREGISTER as you initially suggested. > > Now do_setlink() deadlock does not happen. > > Ah... Thank you. > > Do you have a reference to use as Reported-by, or its from a > non-public instance ? > > I'll test this shortly: > > diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c > index b64c614a00c4..891e2f60922f 100644 > --- a/net/core/netdev-genl.c > +++ b/net/core/netdev-genl.c > @@ -38,7 +38,8 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp, > u64 xdp_rx_meta = 0; > void *hdr; > > - netdev_assert_locked(netdev); /* note: rtnl_lock may not be held! */ > + /* note: rtnl_lock may or may not be held! */ > + netdev_assert_locked_or_invisible(netdev); > > hdr = genlmsg_iput(rsp, info); > if (!hdr) > @@ -966,7 +967,9 @@ static int netdev_genl_netdevice_event(struct notifier_block *nb, > netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_ADD_NTF); > break; > case NETDEV_UNREGISTER: > + netdev_lock(netdev); > netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_DEL_NTF); > + netdev_unlock(netdev); > break; > case NETDEV_XDP_FEAT_CHANGE: > netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_CHANGE_NTF); Ugh, REGISTER is ops locked we'd need conditional locking here. Stanislav, I can make the REGISTERED notifier fully locked, right? I suspect any new object we add that's protected by the instance lock will want to lock the dev.