| Message ID | 20190529173611.4012579-7-andriin@fb.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | libbpf random fixes | expand |
On 05/29, Andrii Nakryiko wrote: > 0 is a valid FD, so it's better to initialize it to -1, as is done in > other places. Also, technically, BTF type ID 0 is valid (it's a VOID > type), so it's more reliable to check btf_fd, instead of > btf_key_type_id, to determine if there is any BTF associated with a map. > > Acked-by: Song Liu <songliubraving@fb.com> > Signed-off-by: Andrii Nakryiko <andriin@fb.com> > --- > tools/lib/bpf/libbpf.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index c972fa10271f..a27a0351e595 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -1751,7 +1751,7 @@ bpf_object__create_maps(struct bpf_object *obj) > create_attr.key_size = def->key_size; > create_attr.value_size = def->value_size; > create_attr.max_entries = def->max_entries; > - create_attr.btf_fd = 0; > + create_attr.btf_fd = -1; > create_attr.btf_key_type_id = 0; > create_attr.btf_value_type_id = 0; > if (bpf_map_type__is_map_in_map(def->type) && > @@ -1765,11 +1765,11 @@ bpf_object__create_maps(struct bpf_object *obj) > } > > *pfd = bpf_create_map_xattr(&create_attr); > - if (*pfd < 0 && create_attr.btf_key_type_id) { > + if (*pfd < 0 && create_attr.btf_fd >= 0) { > cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); > pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", > map->name, cp, errno); > - create_attr.btf_fd = 0; > + create_attr.btf_fd = -1; This breaks libbpf compatibility with the older kernels. If the kernel doesn't know about btf_fd and we set it to -1, then CHECK_ATTR fails :-( Any objections to converting BTF retries to bpf_capabilities and then knowingly passing bft_fd==0 or proper fd? > create_attr.btf_key_type_id = 0; > create_attr.btf_value_type_id = 0; > map->btf_key_type_id = 0; > @@ -2053,6 +2053,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > char *log_buf; > int ret; > > + if (!insns || !insns_cnt) > + return -EINVAL; > + > memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); > load_attr.prog_type = prog->type; > load_attr.expected_attach_type = prog->expected_attach_type; > @@ -2063,7 +2066,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > load_attr.license = license; > load_attr.kern_version = kern_version; > load_attr.prog_ifindex = prog->prog_ifindex; > - load_attr.prog_btf_fd = prog->btf_fd >= 0 ? prog->btf_fd : 0; > + load_attr.prog_btf_fd = prog->btf_fd; > load_attr.func_info = prog->func_info; > load_attr.func_info_rec_size = prog->func_info_rec_size; > load_attr.func_info_cnt = prog->func_info_cnt; > @@ -2072,8 +2075,6 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > load_attr.line_info_cnt = prog->line_info_cnt; > load_attr.log_level = prog->log_level; > load_attr.prog_flags = prog->prog_flags; > - if (!load_attr.insns || !load_attr.insns_cnt) > - return -EINVAL; > > retry_load: > log_buf = malloc(log_buf_size); > -- > 2.17.1 >
On 07/02, Stanislav Fomichev wrote: > On 05/29, Andrii Nakryiko wrote: > > 0 is a valid FD, so it's better to initialize it to -1, as is done in > > other places. Also, technically, BTF type ID 0 is valid (it's a VOID > > type), so it's more reliable to check btf_fd, instead of > > btf_key_type_id, to determine if there is any BTF associated with a map. > > > > Acked-by: Song Liu <songliubraving@fb.com> > > Signed-off-by: Andrii Nakryiko <andriin@fb.com> > > --- > > tools/lib/bpf/libbpf.c | 13 +++++++------ > > 1 file changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index c972fa10271f..a27a0351e595 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -1751,7 +1751,7 @@ bpf_object__create_maps(struct bpf_object *obj) > > create_attr.key_size = def->key_size; > > create_attr.value_size = def->value_size; > > create_attr.max_entries = def->max_entries; > > - create_attr.btf_fd = 0; > > + create_attr.btf_fd = -1; > > create_attr.btf_key_type_id = 0; > > create_attr.btf_value_type_id = 0; > > if (bpf_map_type__is_map_in_map(def->type) && > > @@ -1765,11 +1765,11 @@ bpf_object__create_maps(struct bpf_object *obj) > > } > > > > *pfd = bpf_create_map_xattr(&create_attr); > > - if (*pfd < 0 && create_attr.btf_key_type_id) { > > + if (*pfd < 0 && create_attr.btf_fd >= 0) { > > cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); > > pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", > > map->name, cp, errno); > > - create_attr.btf_fd = 0; > > + create_attr.btf_fd = -1; > This breaks libbpf compatibility with the older kernels. If the kernel > doesn't know about btf_fd and we set it to -1, then CHECK_ATTR > fails :-( > > Any objections to converting BTF retries to bpf_capabilities and then > knowingly passing bft_fd==0 or proper fd? Oh, nevermind, it looks like you fixed it already in e55d54f43d3f. > > create_attr.btf_key_type_id = 0; > > create_attr.btf_value_type_id = 0; > > map->btf_key_type_id = 0; > > @@ -2053,6 +2053,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > > char *log_buf; > > int ret; > > > > + if (!insns || !insns_cnt) > > + return -EINVAL; > > + > > memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); > > load_attr.prog_type = prog->type; > > load_attr.expected_attach_type = prog->expected_attach_type; > > @@ -2063,7 +2066,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > > load_attr.license = license; > > load_attr.kern_version = kern_version; > > load_attr.prog_ifindex = prog->prog_ifindex; > > - load_attr.prog_btf_fd = prog->btf_fd >= 0 ? prog->btf_fd : 0; > > + load_attr.prog_btf_fd = prog->btf_fd; > > load_attr.func_info = prog->func_info; > > load_attr.func_info_rec_size = prog->func_info_rec_size; > > load_attr.func_info_cnt = prog->func_info_cnt; > > @@ -2072,8 +2075,6 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, > > load_attr.line_info_cnt = prog->line_info_cnt; > > load_attr.log_level = prog->log_level; > > load_attr.prog_flags = prog->prog_flags; > > - if (!load_attr.insns || !load_attr.insns_cnt) > > - return -EINVAL; > > > > retry_load: > > log_buf = malloc(log_buf_size); > > -- > > 2.17.1 > >
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c972fa10271f..a27a0351e595 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1751,7 +1751,7 @@ bpf_object__create_maps(struct bpf_object *obj) create_attr.key_size = def->key_size; create_attr.value_size = def->value_size; create_attr.max_entries = def->max_entries; - create_attr.btf_fd = 0; + create_attr.btf_fd = -1; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; if (bpf_map_type__is_map_in_map(def->type) && @@ -1765,11 +1765,11 @@ bpf_object__create_maps(struct bpf_object *obj) } *pfd = bpf_create_map_xattr(&create_attr); - if (*pfd < 0 && create_attr.btf_key_type_id) { + if (*pfd < 0 && create_attr.btf_fd >= 0) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", map->name, cp, errno); - create_attr.btf_fd = 0; + create_attr.btf_fd = -1; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; map->btf_key_type_id = 0; @@ -2053,6 +2053,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, char *log_buf; int ret; + if (!insns || !insns_cnt) + return -EINVAL; + memset(&load_attr, 0, sizeof(struct bpf_load_program_attr)); load_attr.prog_type = prog->type; load_attr.expected_attach_type = prog->expected_attach_type; @@ -2063,7 +2066,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.license = license; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; - load_attr.prog_btf_fd = prog->btf_fd >= 0 ? prog->btf_fd : 0; + load_attr.prog_btf_fd = prog->btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; load_attr.func_info_cnt = prog->func_info_cnt; @@ -2072,8 +2075,6 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.line_info_cnt = prog->line_info_cnt; load_attr.log_level = prog->log_level; load_attr.prog_flags = prog->prog_flags; - if (!load_attr.insns || !load_attr.insns_cnt) - return -EINVAL; retry_load: log_buf = malloc(log_buf_size);