On Thu, Apr 21, 2022 at 12:39:04AM +0000, Alexander Lobakin wrote: > Fix the following error when building bpftool: > > CLANG profiler.bpf.o > CLANG pid_iter.bpf.o > skeleton/profiler.bpf.c:18:21: error: invalid application of 'sizeof' to an incomplete type 'struct bpf_perf_event_value' > __uint(value_size, sizeof(struct bpf_perf_event_value)); > ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:13:39: note: expanded from macro '__uint' > tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h:7:8: note: forward declaration of 'struct bpf_perf_event_value' > struct bpf_perf_event_value; > ^ > > struct bpf_perf_event_value is being used in the kernel only when > CONFIG_BPF_EVENTS is enabled, so it misses a BTF entry then. > Define struct bpf_perf_event_value___local with the > `preserve_access_index` attribute inside the pid_iter BPF prog to > allow compiling on any configs. It is a full mirror of a UAPI > structure, so is compatible both with and w/o CO-RE. > bpf_perf_event_read_value() requires a pointer of the original type, > so a cast is needed. > Hi Alexander, What's the status of this series? I wasn't able to find a v3 on lore. We received a report that OpenMandriva is carrying around this patch. https://github.com/ClangBuiltLinux/linux/issues/1805. + Tomasz Tomasz, do you have more info which particular configs can reproduce this issue? Is this patch still necessary? > Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command") > Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > Signed-off-by: Alexander Lobakin <alobakin@xxxxx> > --- > tools/bpf/bpftool/skeleton/profiler.bpf.c | 27 ++++++++++++++--------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/tools/bpf/bpftool/skeleton/profiler.bpf.c b/tools/bpf/bpftool/skeleton/profiler.bpf.c > index ce5b65e07ab1..2f80edc682f1 100644 > --- a/tools/bpf/bpftool/skeleton/profiler.bpf.c > +++ b/tools/bpf/bpftool/skeleton/profiler.bpf.c > @@ -4,6 +4,12 @@ > #include <bpf/bpf_helpers.h> > #include <bpf/bpf_tracing.h> > > +struct bpf_perf_event_value___local { > + __u64 counter; > + __u64 enabled; > + __u64 running; > +} __attribute__((preserve_access_index)); > + > /* map of perf event fds, num_cpu * num_metric entries */ > struct { > __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); > @@ -15,14 +21,14 @@ struct { > struct { > __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); > __uint(key_size, sizeof(u32)); > - __uint(value_size, sizeof(struct bpf_perf_event_value)); > + __uint(value_size, sizeof(struct bpf_perf_event_value___local)); > } fentry_readings SEC(".maps"); > > /* accumulated readings */ > struct { > __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); > __uint(key_size, sizeof(u32)); > - __uint(value_size, sizeof(struct bpf_perf_event_value)); > + __uint(value_size, sizeof(struct bpf_perf_event_value___local)); > } accum_readings SEC(".maps"); > > /* sample counts, one per cpu */ > @@ -39,7 +45,7 @@ const volatile __u32 num_metric = 1; > SEC("fentry/XXX") > int BPF_PROG(fentry_XXX) > { > - struct bpf_perf_event_value *ptrs[MAX_NUM_MATRICS]; > + struct bpf_perf_event_value___local *ptrs[MAX_NUM_MATRICS]; > u32 key = bpf_get_smp_processor_id(); > u32 i; > > @@ -53,10 +59,10 @@ int BPF_PROG(fentry_XXX) > } > > for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) { > - struct bpf_perf_event_value reading; > + struct bpf_perf_event_value___local reading; > int err; > > - err = bpf_perf_event_read_value(&events, key, &reading, > + err = bpf_perf_event_read_value(&events, key, (void *)&reading, > sizeof(reading)); > if (err) > return 0; > @@ -68,14 +74,14 @@ int BPF_PROG(fentry_XXX) > } > > static inline void > -fexit_update_maps(u32 id, struct bpf_perf_event_value *after) > +fexit_update_maps(u32 id, struct bpf_perf_event_value___local *after) > { > - struct bpf_perf_event_value *before, diff; > + struct bpf_perf_event_value___local *before, diff; > > before = bpf_map_lookup_elem(&fentry_readings, &id); > /* only account samples with a valid fentry_reading */ > if (before && before->counter) { > - struct bpf_perf_event_value *accum; > + struct bpf_perf_event_value___local *accum; > > diff.counter = after->counter - before->counter; > diff.enabled = after->enabled - before->enabled; > @@ -93,7 +99,7 @@ fexit_update_maps(u32 id, struct bpf_perf_event_value *after) > SEC("fexit/XXX") > int BPF_PROG(fexit_XXX) > { > - struct bpf_perf_event_value readings[MAX_NUM_MATRICS]; > + struct bpf_perf_event_value___local readings[MAX_NUM_MATRICS]; > u32 cpu = bpf_get_smp_processor_id(); > u32 i, zero = 0; > int err; > @@ -102,7 +108,8 @@ int BPF_PROG(fexit_XXX) > /* read all events before updating the maps, to reduce error */ > for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) { > err = bpf_perf_event_read_value(&events, cpu + i * num_cpu, > - readings + i, sizeof(*readings)); > + (void *)(readings + i), > + sizeof(*readings)); > if (err) > return 0; > } > -- > 2.36.0 > >
