From 2fe7857176ad6b70e8b2a318506525410e774f34 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 23 Mar 2016 11:34:36 +0100 Subject: [PATCH] i40iw: avoid potential uninitialized variable use gcc finds that the i40iw_make_cm_node() function in the recently added i40iw driver uses an uninitilized variable as an index into an array if CONFIG_IPV6 is disabled and the driver uses IPv6 mode: drivers/infiniband/hw/i40iw/i40iw_cm.c: In function 'i40iw_make_cm_node': drivers/infiniband/hw/i40iw/i40iw_cm.c:2206:52: error: 'arpindex' may be used uninitialized in this function [-Werror=maybe-uninitialized] ether_addr_copy(cm_node->rem_mac, iwdev->arp_table[arpindex].mac_addr); As far as I can tell, this code path can not be used because the ipv4 variable is always set with CONFIG_IPV6 is disabled, but it's better to be sure and prevent the undefined behavior, as well as shut up that warning in a proper way. This adds an 'else' clause for the case we get the warning about, causing the function to return an error in a controlled way. To avoid adding extra mess with combined io()/#ifdef clauses, I'm also converting the existing #ifdef into a more readable if(IS_ENABLED()) check. Signed-off-by: Arnd Bergmann Fixes: f27b4746f378 ("i40iw: add connection management code") Acked-by: Mustafa Ismail Signed-off-by: Doug Ledford --- drivers/infiniband/hw/i40iw/i40iw_cm.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/infiniband/hw/i40iw/i40iw_cm.c b/drivers/infiniband/hw/i40iw/i40iw_cm.c index 92745d755272..38f917a6c778 100644 --- a/drivers/infiniband/hw/i40iw/i40iw_cm.c +++ b/drivers/infiniband/hw/i40iw/i40iw_cm.c @@ -1992,7 +1992,6 @@ static int i40iw_addr_resolve_neigh(struct i40iw_device *iwdev, /** * i40iw_get_dst_ipv6 */ -#if IS_ENABLED(CONFIG_IPV6) static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr, struct sockaddr_in6 *dst_addr) { @@ -2008,7 +2007,6 @@ static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr, dst = ip6_route_output(&init_net, NULL, &fl6); return dst; } -#endif /** * i40iw_addr_resolve_neigh_ipv6 - resolve neighbor ipv6 address @@ -2016,7 +2014,6 @@ static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr, * @dst_ip: remote ip address * @arpindex: if there is an arp entry */ -#if IS_ENABLED(CONFIG_IPV6) static int i40iw_addr_resolve_neigh_ipv6(struct i40iw_device *iwdev, u32 *src, u32 *dest, @@ -2089,7 +2086,6 @@ static int i40iw_addr_resolve_neigh_ipv6(struct i40iw_device *iwdev, dst_release(dst); return rc; } -#endif /** * i40iw_ipv4_is_loopback - check if loopback @@ -2190,13 +2186,13 @@ static struct i40iw_cm_node *i40iw_make_cm_node( cm_info->loc_addr[0], cm_info->rem_addr[0], oldarpindex); -#if IS_ENABLED(CONFIG_IPV6) - else + else if (IS_ENABLED(CONFIG_IPV6)) arpindex = i40iw_addr_resolve_neigh_ipv6(iwdev, cm_info->loc_addr, cm_info->rem_addr, oldarpindex); -#endif + else + arpindex = -EINVAL; } if (arpindex < 0) { i40iw_pr_err("cm_node arpindex\n");