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authorAndrii Nakryiko <andriin@fb.com>2020-08-13 13:49:39 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-08-13 16:45:41 -0700
commit15728ad3e71c120278105f20fa65b3735e715e0f (patch)
treee3535002fcf2fec5cddcf456ed3a54318289a689 /tools/lib
parent9028bbcc3e12510cac13a9554f1a1e39667a4387 (diff)
libbpf: Fix BTF-defined map-in-map initialization on 32-bit host arches
Libbpf built in 32-bit mode should be careful about not conflating 64-bit BPF pointers in BPF ELF file and host architecture pointers. This patch fixes issue of incorrect initializating of map-in-map inner map slots due to such difference. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200813204945.1020225-4-andriin@fb.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0d48c18d5030..6accddaaedab 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5195,7 +5195,8 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
static int bpf_object__collect_map_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data)
{
- int i, j, nrels, new_sz, ptr_sz = sizeof(void *);
+ const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
+ int i, j, nrels, new_sz;
const struct btf_var_secinfo *vi = NULL;
const struct btf_type *sec, *var, *def;
const struct btf_member *member;
@@ -5244,7 +5245,7 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
vi = btf_var_secinfos(sec) + map->btf_var_idx;
if (vi->offset <= rel.r_offset &&
- rel.r_offset + sizeof(void *) <= vi->offset + vi->size)
+ rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size)
break;
}
if (j == obj->nr_maps) {
@@ -5280,17 +5281,20 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
return -EINVAL;
moff = rel.r_offset - vi->offset - moff;
- if (moff % ptr_sz)
+ /* here we use BPF pointer size, which is always 64 bit, as we
+ * are parsing ELF that was built for BPF target
+ */
+ if (moff % bpf_ptr_sz)
return -EINVAL;
- moff /= ptr_sz;
+ moff /= bpf_ptr_sz;
if (moff >= map->init_slots_sz) {
new_sz = moff + 1;
- tmp = realloc(map->init_slots, new_sz * ptr_sz);
+ tmp = realloc(map->init_slots, new_sz * host_ptr_sz);
if (!tmp)
return -ENOMEM;
map->init_slots = tmp;
memset(map->init_slots + map->init_slots_sz, 0,
- (new_sz - map->init_slots_sz) * ptr_sz);
+ (new_sz - map->init_slots_sz) * host_ptr_sz);
map->init_slots_sz = new_sz;
}
map->init_slots[moff] = targ_map;