drop_monitor: work around gcc-10 stringop-overflow warning (dc30b405) · Commits · 戴 / test

The current gcc-10 snapshot produces a false-positive warning: net/core/drop_monitor.c: In function 'trace_drop_common.constprop': cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=] In file included from net/core/drop_monitor.c:23: include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here 36 | __u32 entries; | ^~~~~~~ I reported this in the gcc bugzilla, but in case it does not get fixed in the release, work around it by using a temporary variable. Fixes: ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol") Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881 Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Acked-by:

Neil Horman <nhorman@tuxdriver.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/drop_monitor.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -213,6 +213,7 @@ static void sched_send_work(struct timer_list *t)
		static void trace_drop_common(struct sk_buff skb, void location)
		{
		struct net_dm_alert_msg *msg;
		struct net_dm_drop_point *point;
		struct nlmsghdr *nlh;
		struct nlattr *nla;
		int i;
		@@ -231,11 +232,13 @@ static void trace_drop_common(struct sk_buff skb, void location)
		nlh = (struct nlmsghdr *)dskb->data;
		nla = genlmsg_data(nlmsg_data(nlh));
		msg = nla_data(nla);
		point = msg->points;
		for (i = 0; i < msg->entries; i++) {
		if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
		msg->points[i].count++;
		if (!memcmp(&location, &point->pc, sizeof(void *))) {
		point->count++;
		goto out;
		}
		point++;
		}
		if (msg->entries == dm_hit_limit)
		goto out;
		@@ -244,8 +247,8 @@ static void trace_drop_common(struct sk_buff skb, void location)
		*/
		__nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
		nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
		memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
		msg->points[msg->entries].count = 1;
		memcpy(point->pc, &location, sizeof(void *));
		point->count = 1;
		msg->entries++;

		if (!timer_pending(&data->send_timer)) {

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