Infiniband: could not get ARP entries: failed to parse ARP entry about procfs HOT 2 CLOSED

The fix for this was already merged. Issue can be closed.

from procfs.

This is caused by the fact that /proc/net/arp only includes the first nine bytes of the link-layer address.

cf. net/ipv4/arp.c:

#define HBUFFERLEN 30

static void arp_format_neigh_entry(struct seq_file *seq,
				   struct neighbour *n)
{
	char hbuffer[HBUFFERLEN];
...
	for (k = 0, j = 0; k < HBUFFERLEN - 3 && j < dev->addr_len; j++) {
		hbuffer[k++] = hex_asc_hi(n->ha[j]);
		hbuffer[k++] = hex_asc_lo(n->ha[j]);
		hbuffer[k++] = ':';
	}
...
	sprintf(tbuf, "%pI4", n->primary_key);
	seq_printf(seq, "%-16s 0x%-10x0x%-10x%-17s     *        %s\n",
		   tbuf, hatype, arp_state_to_flags(n), hbuffer, dev->name);
...
}

hbuffer is only large enough to hold up to 30 chars of human-readable (hex-formatted with colons) link-layer address. The for-loop in the arp_format_neigh_entry function will truncate a 20-byte InfiniBand link-layer address, e.g. 00:00:00:00:fe:80:00:00:00:00:00:00:02:00:5e:10:00:00:00:01, to 9 bytes, e.g. 00:00:00:00:fe:80:00:00:00, causing net.ParseMAC() to throw an error.

from procfs.