From 3b4130418f62b0e7a4685cc2c03bb41c6cb8922d Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Mon, 13 Jan 2020 23:26:47 -0800 Subject: bpf: Fix seq_show for BPF_MAP_TYPE_STRUCT_OPS Instead of using bpf_struct_ops_map_lookup_elem() which is not implemented, bpf_struct_ops_map_seq_show_elem() should also use bpf_struct_ops_map_sys_lookup_elem() which does an inplace update to the value. The change allocates a value to pass to bpf_struct_ops_map_sys_lookup_elem(). [root@arch-fb-vm1 bpf]# cat /sys/fs/bpf/dctcp {{{1}},BPF_STRUCT_OPS_STATE_INUSE,{{00000000df93eebc,00000000df93eebc},0,2, ... Fixes: 85d33df357b6 ("bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS") Reported-by: Dan Carpenter Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200114072647.3188298-1-kafai@fb.com --- kernel/bpf/bpf_struct_ops.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index ddf48f49914b..8ad1c9ea26b2 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -496,14 +496,20 @@ static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key, struct seq_file *m) { void *value; + int err; - value = bpf_struct_ops_map_lookup_elem(map, key); + value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN); if (!value) return; - btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id, - value, m); - seq_puts(m, "\n"); + err = bpf_struct_ops_map_sys_lookup_elem(map, key, value); + if (!err) { + btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id, + value, m); + seq_puts(m, "\n"); + } + + kfree(value); } static void bpf_struct_ops_map_free(struct bpf_map *map) -- cgit v1.2.3-59-g8ed1b