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 54A181367; Thu, 25 Sep 2025 00:09:17 +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=1758758960; cv=none; b=RV9+H7DPYLtRkHXg6NVbZy76JL+yU/zFOD63ML0EVlpiDrwDcZp5tFwIw9df5/V8ucGWswcceA2t9E7nbkBj/DVBn1grMITVdfURiwyD1EUN2A2qEUmqK9Zm5xvIE/17xzBGGDIVOxUkwDgiv10NEPv+U0AwD42vbSmrzQJNgT4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758758960; c=relaxed/simple; bh=zXw5DYxwpEjeQXD/5cFfmv69GmzKNfiIIaJv56tI04M=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=cRlRHHCQWygkSwZox1YBRCDq5FBYOYrv0IWdteP7WISuQrq698kpE8drdYD1wsyopek/i3V4mq9WTZv5qnMPRE0rB9b8zLQVA4AwcOE0n6D6DI1vtvJDWBUMwyPozFNNYVccd1eaKedTKi3W7ydK/FjdKsVElvkx3uJhtwkqcgM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DcwMnP+f; 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="DcwMnP+f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB108C4CEE7; Thu, 25 Sep 2025 00:09:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758758956; bh=zXw5DYxwpEjeQXD/5cFfmv69GmzKNfiIIaJv56tI04M=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=DcwMnP+fSTTIt6L/+/KYWD65ImSA1ZyK84T8BFjldMZStL68YdKe0cLtbRVC7y+1o 0x87AVC4yQVu+Qtg2Pl1x2+GwCmkzklr+WF2ZrcA0OsAykBRWCxqYYLalOVP2o9Mxb HnxFgM1GdMLKnbO1BzHkzCAAV9Z9rVUqpdKqOiq/D4eIQCTNYBURM5jE/ElHYS7utZ sy1oRohUrz14S1yzl3pt6TtnEX7jQqQnA/nCfHKMjk31FOEDAfPgKt+QrkEUfQvqOf +x2+ss6HLzrRZaKsE1FmCl//jCxNptXigCUDsY6MN5xjY6g71c34Li5873B5ZzNOZO UGMqy6Jo2+0dg== Date: Wed, 24 Sep 2025 17:09:14 -0700 From: Jakub Kicinski To: Octavian Purdila Cc: 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, uniyu@google.com, ahmed.zaki@intel.com, aleksander.lobakin@intel.com, toke@redhat.com, lorenzo@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, syzbot+ff145014d6b0ce64a173@syzkaller.appspotmail.com Subject: Re: [PATCH net] xdp: use multi-buff only if receive queue supports page pool Message-ID: <20250924170914.20aac680@kernel.org> In-Reply-To: <20250924060843.2280499-1-tavip@google.com> References: <20250924060843.2280499-1-tavip@google.com> 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, 24 Sep 2025 06:08:42 +0000 Octavian Purdila wrote: > When a BPF program that supports BPF_F_XDP_HAS_FRAGS is issuing > bpf_xdp_adjust_tail and a large packet is injected via /dev/net/tun a > crash occurs due to detecting a bad page state (page_pool leak). > > This is because xdp_buff does not record the type of memory and > instead relies on the netdev receive queue xdp info. Since the TUN/TAP > driver is using a MEM_TYPE_PAGE_SHARED memory model buffer, shrinking > will eventually call page_frag_free. But with current multi-buff > support for BPF_F_XDP_HAS_FRAGS programs buffers are allocated via the > page pool. > > To fix this issue check that the receive queue memory mode is of > MEM_TYPE_PAGE_POOL before using multi-buffs. This can also happen on veth, right? And veth re-stamps the Rx queues.