On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by
> hashed index")
> Reported-by: Tetsuo Handa <[email protected]>
> Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
@@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union
bpf_attr *attr)
cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
cost += sizeof(struct list_head) * num_possible_cpus();
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
+
+ if (!dtab->n_buckets) /* Overflow check */
+ return -EINVAL;
+ cost += sizeof(struct hlist_head) * dtab->n_buckets;
^here
+ }
+
/* if map size is larger than memlock limit, reject it */
err = bpf_map_charge_init(&dtab->map.memory, cost);
if (err)
like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can
become 0.
----------
#include <stdio.h>
#include <linux/types.h>
int main(int argc, char *argv[])
{
volatile __u32 i = 4294967296ULL / sizeof(unsigned long *);
volatile __u64 cost = sizeof(unsigned long *) * i;
printf("cost=%llu\n", (unsigned long long) cost);
return 0;
}
----------
