From 2874c5fd284268364ece81a7bd936f3c8168e567 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 27 May 2019 08:55:01 +0200 Subject: treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman --- net/core/pktgen.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'net/core/pktgen.c') diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 319ad5490fb3..99ddc69736b2 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Authors: * Copyright 2001, 2002 by Robert Olsson @@ -8,12 +9,6 @@ * Ben Greear * Jens Låås * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - * * A tool for loading the network with preconfigurated packets. * The tool is implemented as a linux module. Parameters are output * device, delay (to hard_xmit), number of packets, and whether @@ -60,7 +55,6 @@ * * Integrated to 2.5.x 021029 --Lucio Maciel (luciomaciel@zipmail.com.br) * - * * 021124 Finished major redesign and rewrite for new functionality. * See Documentation/networking/pktgen.txt for how to use this. * @@ -114,7 +108,6 @@ * * Fixed src_mac command to set source mac of packet to value specified in * command by Adit Ranadive - * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -- cgit v1.2.3 From 720f1de4021f09898b8c8443f3b3e995991b6e3a Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 6 Jun 2019 15:45:03 +0200 Subject: pktgen: do not sleep with the thread lock held. Currently, the process issuing a "start" command on the pktgen procfs interface, acquires the pktgen thread lock and never release it, until all pktgen threads are completed. The above can blocks indefinitely any other pktgen command and any (even unrelated) netdevice removal - as the pktgen netdev notifier acquires the same lock. The issue is demonstrated by the following script, reported by Matteo: ip -b - <<'EOF' link add type dummy link add type veth link set dummy0 up EOF modprobe pktgen echo reset >/proc/net/pktgen/pgctrl { echo rem_device_all echo add_device dummy0 } >/proc/net/pktgen/kpktgend_0 echo count 0 >/proc/net/pktgen/dummy0 echo start >/proc/net/pktgen/pgctrl & sleep 1 rmmod veth Fix the above releasing the thread lock around the sleep call. Additionally we must prevent racing with forcefull rmmod - as the thread lock no more protects from them. Instead, acquire a self-reference before waiting for any thread. As a side effect, running rmmod pktgen while some thread is running now fails with "module in use" error, before this patch such command hanged indefinitely. Note: the issue predates the commit reported in the fixes tag, but this fix can't be applied before the mentioned commit. v1 -> v2: - no need to check for thread existence after flipping the lock, pktgen threads are freed only at net exit time - Fixes: 6146e6a43b35 ("[PKTGEN]: Removes thread_{un,}lock() macros.") Reported-and-tested-by: Matteo Croce Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/core/pktgen.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'net/core/pktgen.c') diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 319ad5490fb3..a33d03c05ed6 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3066,7 +3066,13 @@ static int pktgen_wait_thread_run(struct pktgen_thread *t) { while (thread_is_running(t)) { + /* note: 't' will still be around even after the unlock/lock + * cycle because pktgen_thread threads are only cleared at + * net exit + */ + mutex_unlock(&pktgen_thread_lock); msleep_interruptible(100); + mutex_lock(&pktgen_thread_lock); if (signal_pending(current)) goto signal; @@ -3081,6 +3087,10 @@ static int pktgen_wait_all_threads_run(struct pktgen_net *pn) struct pktgen_thread *t; int sig = 1; + /* prevent from racing with rmmod */ + if (!try_module_get(THIS_MODULE)) + return sig; + mutex_lock(&pktgen_thread_lock); list_for_each_entry(t, &pn->pktgen_threads, th_list) { @@ -3094,6 +3104,7 @@ static int pktgen_wait_all_threads_run(struct pktgen_net *pn) t->control |= (T_STOP); mutex_unlock(&pktgen_thread_lock); + module_put(THIS_MODULE); return sig; } -- cgit v1.2.3