From 5bd9e4e7cdaa03879e9b73b12ab52cceb1edd55b Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Thu, 3 Sep 2026 11:02:59 +0300 Subject: [PATCH] nexthop: Initialize extack in remove_nh_grp_entry() remove_nh_grp_entry() prints the extack message when a listener fails to replace the reduced nexthop group. However, extack is not initialized and listeners are not required to set a message when returning an error. Neither netdevsim nor mlxsw do so when an allocation fails, resulting in the dereference of an uninitialized stack pointer. Fix by zero-initializing extack, as was done in commit 6347c5314cee ("nexthop: initialize extack in nh_res_bucket_migrate()"). Fixes: 833a1065eeb1 ("nexthop: Emit a notification when a nexthop group is reduced") Signed-off-by: Ido Schimmel Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260903080259.10378-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski --- net/ipv4/nexthop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c index a7c2b8dced4e..42e55b5a755e 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -2036,7 +2036,7 @@ remove_nh_grp_entry(struct net *net, struct nh_grp_entry *nhge, { struct nh_grp_entry *nhges, *new_nhges; struct nexthop *nhp = nhge->nh_parent; - struct netlink_ext_ack extack; + struct netlink_ext_ack extack = {}; struct nexthop *nh = nhge->nh; struct nh_group *nhg, *newg; int i, j, err;