4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Sven Eckelmann <[email protected]> commit 955d3411a17f590364238bd0d3329b61f20c1cd2 upstream. It is not allowed to use WARN* helpers on potential incorrect input from the user or transient problems because systems configured as panic_on_warn will reboot due to such a problem. A NULL return value of __dev_get_by_index can be caused by various problems which can either be related to the system configuration or problems (incorrectly returned network namespaces) in other (virtual) net_device drivers. batman-adv should not cause a (harmful) WARN in this situation and instead only report it via a simple message. Fixes: b7eddd0b3950 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") Reported-by: [email protected] Reported-by: Dmitry Vyukov <[email protected]> Signed-off-by: Sven Eckelmann <[email protected]> Signed-off-by: Simon Wunderlich <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/batman-adv/hard-interface.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -18,7 +18,6 @@ #include "hard-interface.h" #include "main.h" -#include <linux/bug.h> #include <linux/byteorder/generic.h> #include <linux/errno.h> #include <linux/fs.h> @@ -104,8 +103,10 @@ static bool batadv_is_on_batman_iface(co /* recurse over the parent device */ parent_dev = __dev_get_by_index(&init_net, dev_get_iflink(net_dev)); /* if we got a NULL parent_dev there is something broken.. */ - if (WARN(!parent_dev, "Cannot find parent device")) + if (!parent_dev) { + pr_err("Cannot find parent device\n"); return false; + } ret = batadv_is_on_batman_iface(parent_dev);
