| Message ID | 20220414223704.341028-3-alobakin@pm.me (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: random unpopular userspace fixes (32 bit et al.) | expand |
On Thu, Apr 14, 2022 at 3:45 PM Alexander Lobakin <alobakin@pm.me> wrote: > > When building bpftool with !CONFIG_PERF_EVENTS: > > skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link' > perf_link = container_of(link, struct bpf_perf_link, link); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of' > ((type *)(__mptr - offsetof(type, member))); \ > ^~~~~~~~~~~~~~~~~~~~~~ > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof' > #define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER) > ~~~~~~~~~~~^ > skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link' > struct bpf_perf_link *perf_link; > ^ > > &bpf_perf_link is being defined and used only under the ifdef. > Move it out of the block and explicitly emit a BTF to fix > compilation. > > Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output") > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Similar to v1, this fix is weird to me. I hope we have can fix it in user space.
From: Song Liu <song@kernel.org> Date: Fri, 15 Apr 2022 16:24:41 -0700 > On Thu, Apr 14, 2022 at 3:45 PM Alexander Lobakin <alobakin@pm.me> wrote: > > > > When building bpftool with !CONFIG_PERF_EVENTS: > > > > skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link' > > perf_link = container_of(link, struct bpf_perf_link, link); > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of' > > ((type *)(__mptr - offsetof(type, member))); \ > > ^~~~~~~~~~~~~~~~~~~~~~ > > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof' > > #define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER) > > ~~~~~~~~~~~^ > > skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link' > > struct bpf_perf_link *perf_link; > > ^ > > > > &bpf_perf_link is being defined and used only under the ifdef. > > Move it out of the block and explicitly emit a BTF to fix > > compilation. > > > > Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output") > > Signed-off-by: Alexander Lobakin <alobakin@pm.me> > > Similar to v1, this fix is weird to me. I hope we have can fix it in user > space. I've been thinking on this, but userspace is not provided with any autoconf.h definitions (only selftests have them), so its code must be sort of universal. Both this and 01/11 are compile time and due to imcomplete and/or absent BTF struct declarations. I'm not familiar with bpf_core_field_exists(), and it might be that it's able to solve 01/11, but not this one. &bpf_perf_link must be present unconditionally, otherwise it won't be defined in the generated vmlinux.h at all. Thanks, Al
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index e9621cfa09f2..34fdf27d14cf 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2952,12 +2952,12 @@ static const struct bpf_link_ops bpf_raw_tp_link_lops = { .fill_link_info = bpf_raw_tp_link_fill_link_info, }; -#ifdef CONFIG_PERF_EVENTS struct bpf_perf_link { struct bpf_link link; struct file *perf_file; }; +#ifdef CONFIG_PERF_EVENTS static void bpf_perf_link_release(struct bpf_link *link) { struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link); @@ -4333,6 +4333,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) #endif case BPF_PROG_TYPE_PERF_EVENT: case BPF_PROG_TYPE_TRACEPOINT: + BTF_TYPE_EMIT(struct bpf_perf_link); ret = bpf_perf_link_attach(attr, prog); break; case BPF_PROG_TYPE_KPROBE:
When building bpftool with !CONFIG_PERF_EVENTS: skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link' perf_link = container_of(link, struct bpf_perf_link, link); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of' ((type *)(__mptr - offsetof(type, member))); \ ^~~~~~~~~~~~~~~~~~~~~~ tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof' #define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER) ~~~~~~~~~~~^ skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link' struct bpf_perf_link *perf_link; ^ &bpf_perf_link is being defined and used only under the ifdef. Move it out of the block and explicitly emit a BTF to fix compilation. Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output") Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- kernel/bpf/syscall.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.35.2