batman-adv/patches/0022-batman-adv-Avoid-WARN-on-net_device-without-parent-i.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Sun, 30 Dec 2018 12:46:01 +0100
   3 Subject: batman-adv: Avoid WARN on net_device without parent in netns
   4
   5 It is not allowed to use WARN* helpers on potential incorrect input from
   6 the user or transient problems because systems configured as panic_on_warn
   7 will reboot due to such a problem.
   8
   9 A NULL return value of __dev_get_by_index can be caused by various problems
  10 which can either be related to the system configuration or problems
  11 (incorrectly returned network namespaces) in other (virtual) net_device
  12 drivers. batman-adv should not cause a (harmful) WARN in this situation and
  13 instead only report it via a simple message.
  14
  15 Fixes: 3d48811b27f5 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface")
  16 Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com
  17 Reported-by: Dmitry Vyukov <dvyukov@google.com>
  18 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  19
  20 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/59ad04405be86f648fd83d81d2fd0a78f215a43b
  21
  22 diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
  23 index 2f0d42f2f913e74cf10c0c6ce89320434994cac5..08690d06b7be2b25ca3f009394763c7083c70644 100644
  24 --- a/net/batman-adv/hard-interface.c
  25 +++ b/net/batman-adv/hard-interface.c
  26 @@ -20,7 +20,6 @@
  27  #include "main.h"
  28
  29  #include <linux/atomic.h>
  30 -#include <linux/bug.h>
  31  #include <linux/byteorder/generic.h>
  32  #include <linux/errno.h>
  33  #include <linux/gfp.h>
  34 @@ -179,8 +178,10 @@ static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
  35         parent_dev = __dev_get_by_index((struct net *)parent_net,
  36                                         dev_get_iflink(net_dev));
  37         /* if we got a NULL parent_dev there is something broken.. */
  38 -       if (WARN(!parent_dev, "Cannot find parent device"))
  39 +       if (!parent_dev) {
  40 +               pr_err("Cannot find parent device\n");
  41                 return false;
  42 +       }
  43
  44         if (batadv_mutual_parents(net_dev, net, parent_dev, parent_net))
  45                 return false;