From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fhigh-a8-smtp.messagingengine.com (fhigh-a8-smtp.messagingengine.com [103.168.172.159]) (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 4BAA026D5C8 for ; Tue, 18 Feb 2025 15:21:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.159 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739892106; cv=none; b=BaRnoeLE/Lc9CYT2P0AL8feV3AgBF/7mTl2JRBhe8ozbziSNpbs1NGS3Iv0hQabMy6Kv4gdfOMrzHKxNOBF8dwfsMtP4n26530Ug4WlVT0IVegYOeuEy1Rt+prinXU5KMFoxCU98UuZssPctj1RZ+/3agsvC56MdXJWbiR2swKw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739892106; c=relaxed/simple; bh=6WtVAfAhOQBhmPNF3eva73UYC/Wsc3+i+rBcWuwzoCY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Cv1LqTFDb3teyDaIpW4mTg/9Z3r9bUDgcCpYrBlkWMLRi4jggUbnhOO7gxM9vAd5Q9L8SKUhtJhW77EkiXJ4utYDqolW5H6yFvkxxwXlMKeNdh6CyikL97yyQfw9ylP9fzMK2a/IrY8yx3JbISRZUOrK3g0kZqTXWopXby28rEY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=idosch.org; spf=none smtp.mailfrom=idosch.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=BjcBlLn2; arc=none smtp.client-ip=103.168.172.159 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=idosch.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=idosch.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="BjcBlLn2" Received: from phl-compute-02.internal (phl-compute-02.phl.internal [10.202.2.42]) by mailfhigh.phl.internal (Postfix) with ESMTP id 4E935114023B; Tue, 18 Feb 2025 10:21:43 -0500 (EST) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-02.internal (MEProxy); Tue, 18 Feb 2025 10:21:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t=1739892103; x= 1739978503; bh=ESiXGQA7LoMCz2qROe4jft1yBdvs96YNdMTAzY4Vrik=; b=B jcBlLn2TJVPo+XQ7fTaCQStL19HdyoB3szzpWCNW0MKZqdEYt4ANamBmIj6W2H+2 T30RXAI8ei/d/YbyzLvF5VOrJnvDA9IRPQYyrEu/lOodfsXiBKo50opDo9SP0EBR 3ix8Lkj0JEx+Grr5VdDVzpLeqS6MhX0iBzsDvYv8+OJScNpZuxMGQdxkeUAbjczL v9lQdG0/RyIfasREMWD/aYlrvzC1DuJuft581Zwpbe49+Wdscjxy/IVpT5fUWQvq 2iJeo522ocGQJsoJ17f8hJS+0h2Qr9kE6vTARMLXdeHrXo4W9KrS/0R0KjE83dSt m2ZD3blIFCeIWX2mF35nw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdeiudeiiecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdp uffrtefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivg hnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtugfgjgesthekredttddt jeenucfhrhhomhepkfguohcuufgthhhimhhmvghluceoihguohhstghhsehiughoshgthh drohhrgheqnecuggftrfgrthhtvghrnhepkeeggfeghfeuvdegtedtgedvuedvhfdujedv vdejteelvdeutdehheellefhhfdunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrg hmpehmrghilhhfrhhomhepihguohhstghhsehiughoshgthhdrohhrghdpnhgspghrtghp thhtohepiedpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtoheplhhutghivghnrdigih hnsehgmhgrihhlrdgtohhmpdhrtghpthhtohepshhtvghphhgvnhesnhgvthifohhrkhhp lhhumhgsvghrrdhorhhgpdhrtghpthhtohepvgguuhhmrgiivghtsehgohhoghhlvgdrtg homhdprhgtphhtthhopehnvghtuggvvhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgt phhtthhopehfmhgvihesshhfshdrtghomhdprhgtphhtthhopeifvghifigrnhesghhooh hglhgvrdgtohhm X-ME-Proxy: Feedback-ID: i494840e7:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 18 Feb 2025 10:21:41 -0500 (EST) Date: Tue, 18 Feb 2025 17:21:38 +0200 From: Ido Schimmel To: Xin Long Cc: Stephen Hemminger , edumazet@google.com, netdev@vger.kernel.org, fmei@sfs.com, Wei Wang Subject: Re: Fw: [Bug 219766] New: Garbage Ethernet Frames Message-ID: References: <20250210084931.23a5c2e4@hermes.local> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Feb 17, 2025 at 05:31:16PM -0500, Xin Long wrote: > On Sat, Feb 15, 2025 at 3:47 PM Ido Schimmel wrote: > > Another possible solution is to have the blackhole device consume the > > packets instead of letting them go out without an Ethernet header [4]. > > Doesn't seem great as the packets disappear without telling anyone > > (before 22600596b675 an error was returned). > This looks fine to me. The fix in commit 22600596b675 was specifically > intended to prevent an error from being returned in these cases, as it > would break userspace UDP applications. Yes, I later realized that this is fine as well. Packets are already discarded today via dst_discard_out() if dst_dev_put() was called on a dst entry before calling dst_output(): # bpftrace -e 'k:dst_discard_out { @[kstack()] = count(); }' Attaching 1 probe... ^C @[ dst_discard_out+5 ip_send_skb+25 udp_send_skb+376 udp_sendmsg+2516 sock_write_iter+365 vfs_write+937 ksys_write+200 do_syscall_64+158 entry_SYSCALL_64_after_hwframe+119 ]: 2034 While running the reproducer I shared earlier. > If you prefer to avoid silent drops, you could add a warning like: > > net_warn_ratelimited("%s(): Dropping skb.\n", __func__); > > similar to how blackhole_netdev_xmit() handles it. I would like to avoid spamming the kernel log with these messages. I checked and we see these messages on a few machines while running the IPv6 torture tests in fib_nexthops.sh. Maybe in net-next I will add a new drop reason for these scenarios. > Thanks. Thanks. I will run this patch through regression and post later this week if everything is fine.