| Message ID | 20220730000809.312891-1-sdf@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,1/2] bpf: use proper target btf when exporting attach_btf_obj_id | expand |
On Fri, Jul 29, 2022 at 5:08 PM Stanislav Fomichev <sdf@google.com> wrote: > > When attaching to program, the program itself might not be attached > to anything (and, hence, might not have attach_btf), so we can't > unconditionally use 'prog->aux->dst_prog->aux->attach_btf'. > Instead, use bpf_prog_get_target_btf to pick proper target btf: > > * when attached to dst_prog, use dst_prog->aux->btf > * when attached to kernel btf, use prog->aux->attach_btf > > Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP") > Signed-off-by: Stanislav Fomichev <sdf@google.com> Looks good to me. Acked-by: Hao Luo <haoluo@google.com> Hao
On Fri, Jul 29, 2022 at 05:08:08PM -0700, Stanislav Fomichev wrote: > When attaching to program, the program itself might not be attached > to anything (and, hence, might not have attach_btf), so we can't > unconditionally use 'prog->aux->dst_prog->aux->attach_btf'. > Instead, use bpf_prog_get_target_btf to pick proper target btf: > > * when attached to dst_prog, use dst_prog->aux->btf > * when attached to kernel btf, use prog->aux->attach_btf > > Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP") > Signed-off-by: Stanislav Fomichev <sdf@google.com> > --- > kernel/bpf/syscall.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 83c7136c5788..7dc3f8003631 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3886,6 +3886,7 @@ static int bpf_prog_get_info_by_fd(struct file *file, > union bpf_attr __user *uattr) > { > struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info); > + struct btf *attach_btf = bpf_prog_get_target_btf(prog); > struct bpf_prog_info info; > u32 info_len = attr->info.info_len; > struct bpf_prog_kstats stats; > @@ -4088,10 +4089,8 @@ static int bpf_prog_get_info_by_fd(struct file *file, > if (prog->aux->btf) > info.btf_id = btf_obj_id(prog->aux->btf); > info.attach_btf_id = prog->aux->attach_btf_id; > - if (prog->aux->attach_btf) > - info.attach_btf_obj_id = btf_obj_id(prog->aux->attach_btf); > - else if (prog->aux->dst_prog) > - info.attach_btf_obj_id = btf_obj_id(prog->aux->dst_prog->aux->attach_btf); > + if (attach_btf) > + info.attach_btf_obj_id = btf_obj_id(attach_btf); Nice. Acked-by: Martin KaFai Lau <kafai@fb.com>
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 83c7136c5788..7dc3f8003631 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3886,6 +3886,7 @@ static int bpf_prog_get_info_by_fd(struct file *file, union bpf_attr __user *uattr) { struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info); + struct btf *attach_btf = bpf_prog_get_target_btf(prog); struct bpf_prog_info info; u32 info_len = attr->info.info_len; struct bpf_prog_kstats stats; @@ -4088,10 +4089,8 @@ static int bpf_prog_get_info_by_fd(struct file *file, if (prog->aux->btf) info.btf_id = btf_obj_id(prog->aux->btf); info.attach_btf_id = prog->aux->attach_btf_id; - if (prog->aux->attach_btf) - info.attach_btf_obj_id = btf_obj_id(prog->aux->attach_btf); - else if (prog->aux->dst_prog) - info.attach_btf_obj_id = btf_obj_id(prog->aux->dst_prog->aux->attach_btf); + if (attach_btf) + info.attach_btf_obj_id = btf_obj_id(attach_btf); ulen = info.nr_func_info; info.nr_func_info = prog->aux->func_info_cnt;
When attaching to program, the program itself might not be attached to anything (and, hence, might not have attach_btf), so we can't unconditionally use 'prog->aux->dst_prog->aux->attach_btf'. Instead, use bpf_prog_get_target_btf to pick proper target btf: * when attached to dst_prog, use dst_prog->aux->btf * when attached to kernel btf, use prog->aux->attach_btf Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP") Signed-off-by: Stanislav Fomichev <sdf@google.com> --- kernel/bpf/syscall.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)