From patchwork Tue Jul 2 15:04:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 1126281 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45dSFR3Rk4z9sNC for ; Wed, 3 Jul 2019 01:04:27 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbfGBPEX (ORCPT ); Tue, 2 Jul 2019 11:04:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59770 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725981AbfGBPEW (ORCPT ); Tue, 2 Jul 2019 11:04:22 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1B47730860B0; Tue, 2 Jul 2019 15:04:22 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-219.rdu2.redhat.com [10.10.120.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id EFFD978361; Tue, 2 Jul 2019 15:04:20 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net] rxrpc: Fix oops in tracepoint From: David Howells To: netdev@vger.kernel.org Cc: Marc Dionne , dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Tue, 02 Jul 2019 16:04:19 +0100 Message-ID: <156207985906.2089.12488693451155589820.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Tue, 02 Jul 2019 15:04:22 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If the rxrpc_eproto tracepoint is enabled, an oops will be cause by the trace line that rxrpc_extract_header() tries to emit when a protocol error occurs (typically because the packet is short) because the call argument is NULL. Fix this by using ?: to assume 0 as the debug_id if call is NULL. This can then be induced by: echo -e '\0\0\0\0\0\0\0\0' | ncat -4u --send-only 20001 where addr has the following program running on it: #include #include #include #include #include #include #include int main(void) { struct sockaddr_rxrpc srx; int fd; memset(&srx, 0, sizeof(srx)); srx.srx_family = AF_RXRPC; srx.srx_service = 0; srx.transport_type = AF_INET; srx.transport_len = sizeof(srx.transport.sin); srx.transport.sin.sin_family = AF_INET; srx.transport.sin.sin_port = htons(0x4e21); fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET6); bind(fd, (struct sockaddr *)&srx, sizeof(srx)); sleep(20); return 0; } It results in the following oops. BUG: kernel NULL pointer dereference, address: 0000000000000340 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page ... RIP: 0010:trace_event_raw_event_rxrpc_rx_eproto+0x47/0xac ... Call Trace: rxrpc_extract_header+0x86/0x171 ? rcu_read_lock_sched_held+0x5d/0x63 ? rxrpc_new_skb+0xd4/0x109 rxrpc_input_packet+0xef/0x14fc ? rxrpc_input_data+0x986/0x986 udp_queue_rcv_one_skb+0xbf/0x3d0 udp_unicast_rcv_skb.isra.8+0x64/0x71 ip_protocol_deliver_rcu+0xe4/0x1b4 ip_local_deliver+0xf0/0x154 __netif_receive_skb_one_core+0x50/0x6c netif_receive_skb_internal+0x26b/0x2e9 napi_gro_receive+0xf8/0x1da rtl8169_poll+0x303/0x4c4 net_rx_action+0x10e/0x333 __do_softirq+0x1a5/0x38f irq_exit+0x54/0xc4 do_IRQ+0xda/0xf8 common_interrupt+0xf/0xf ... ? cpuidle_enter_state+0x23c/0x34d cpuidle_enter+0x2a/0x36 do_idle+0x163/0x1ea cpu_startup_entry+0x1d/0x1f start_secondary+0x157/0x172 secondary_startup_64+0xa4/0xb0 Fixes: a25e21f0bcd2 ("rxrpc, afs: Use debug_ids rather than pointers in traces") Signed-off-by: David Howells Reviewed-by: Marc Dionne --- include/trace/events/rxrpc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index d85816878a52..cc1d060cbf13 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -1379,7 +1379,7 @@ TRACE_EVENT(rxrpc_rx_eproto, ), TP_fast_assign( - __entry->call = call->debug_id; + __entry->call = call ? call->debug_id : 0; __entry->serial = serial; __entry->why = why; ),