In hwsim_dump_radio_nl(), when genlmsg_put() on line 3617 fails, hdr is assigned to NULL. Then hdr is used on lines 3622 and 3623: genl_dump_check_consistent(cb, hdr); genlmsg_end(skb, hdr); Thus, possible null-pointer dereferences may occur. To fix these bugs, hdr is used here when it is not NULL. This bug is found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx> --- drivers/net/wireless/mac80211_hwsim.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index 519b4ee88c5c..61a8b6429e09 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -3617,10 +3617,11 @@ static int hwsim_dump_radio_nl(struct sk_buff *skb, hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, &hwsim_genl_family, NLM_F_MULTI, HWSIM_CMD_GET_RADIO); - if (!hdr) + if (hdr) { + genl_dump_check_consistent(cb, hdr); + genlmsg_end(skb, hdr); + } else res = -EMSGSIZE; - genl_dump_check_consistent(cb, hdr); - genlmsg_end(skb, hdr); } done: -- 2.17.0