132 lines
4.6 KiB
Diff
132 lines
4.6 KiB
Diff
From bf5a83d6f1a9851cd1471fba06a58abbab5bc4c4 Mon Sep 17 00:00:00 2001
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From: Alexander Lobakin <alobakin@pm.me>
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Date: Thu, 21 Apr 2022 00:39:04 +0000
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Subject: [PATCH] bpftool: use a local bpf_perf_event_value to fix accessing
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its fields
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Fix the following error when building bpftool:
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CLANG profiler.bpf.o
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CLANG pid_iter.bpf.o
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skeleton/profiler.bpf.c:18:21: error: invalid application of 'sizeof' to an incomplete type 'struct bpf_perf_event_value'
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__uint(value_size, sizeof(struct bpf_perf_event_value));
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^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:13:39: note: expanded from macro '__uint'
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tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h:7:8: note: forward declaration of 'struct bpf_perf_event_value'
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struct bpf_perf_event_value;
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^
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struct bpf_perf_event_value is being used in the kernel only when
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CONFIG_BPF_EVENTS is enabled, so it misses a BTF entry then.
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Define struct bpf_perf_event_value___local with the
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`preserve_access_index` attribute inside the pid_iter BPF prog to
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allow compiling on any configs. It is a full mirror of a UAPI
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structure, so is compatible both with and w/o CO-RE.
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bpf_perf_event_read_value() requires a pointer of the original type,
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so a cast is needed.
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Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
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Suggested-by: Andrii Nakryiko <andrii@kernel.org>
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Signed-off-by: Alexander Lobakin <alobakin@pm.me>
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Signed-off-by: Quentin Monnet <quentin@isovalent.com>
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---
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tools/bpf/bpftool/skeleton/profiler.bpf.c | 27 ++++++++++++++---------
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1 file changed, 17 insertions(+), 10 deletions(-)
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diff --git a/src/skeleton/profiler.bpf.c b/src/skeleton/profiler.bpf.c
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index ce5b65e07ab1..2f80edc682f1 100644
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--- a/src/skeleton/profiler.bpf.c
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+++ b/src/skeleton/profiler.bpf.c
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@@ -4,6 +4,12 @@
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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+struct bpf_perf_event_value___local {
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+ __u64 counter;
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+ __u64 enabled;
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+ __u64 running;
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+} __attribute__((preserve_access_index));
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+
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/* map of perf event fds, num_cpu * num_metric entries */
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struct {
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__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
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@@ -15,14 +21,14 @@ struct {
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__uint(key_size, sizeof(u32));
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- __uint(value_size, sizeof(struct bpf_perf_event_value));
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+ __uint(value_size, sizeof(struct bpf_perf_event_value___local));
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} fentry_readings SEC(".maps");
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/* accumulated readings */
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__uint(key_size, sizeof(u32));
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- __uint(value_size, sizeof(struct bpf_perf_event_value));
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+ __uint(value_size, sizeof(struct bpf_perf_event_value___local));
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} accum_readings SEC(".maps");
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/* sample counts, one per cpu */
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@@ -39,7 +45,7 @@ const volatile __u32 num_metric = 1;
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SEC("fentry/XXX")
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int BPF_PROG(fentry_XXX)
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{
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- struct bpf_perf_event_value *ptrs[MAX_NUM_MATRICS];
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+ struct bpf_perf_event_value___local *ptrs[MAX_NUM_MATRICS];
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u32 key = bpf_get_smp_processor_id();
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u32 i;
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@@ -53,10 +59,10 @@ int BPF_PROG(fentry_XXX)
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}
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for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) {
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- struct bpf_perf_event_value reading;
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+ struct bpf_perf_event_value___local reading;
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int err;
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- err = bpf_perf_event_read_value(&events, key, &reading,
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+ err = bpf_perf_event_read_value(&events, key, (void *)&reading,
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sizeof(reading));
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if (err)
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return 0;
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@@ -68,14 +74,14 @@ int BPF_PROG(fentry_XXX)
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}
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static inline void
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-fexit_update_maps(u32 id, struct bpf_perf_event_value *after)
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+fexit_update_maps(u32 id, struct bpf_perf_event_value___local *after)
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{
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- struct bpf_perf_event_value *before, diff;
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+ struct bpf_perf_event_value___local *before, diff;
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before = bpf_map_lookup_elem(&fentry_readings, &id);
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/* only account samples with a valid fentry_reading */
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if (before && before->counter) {
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- struct bpf_perf_event_value *accum;
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+ struct bpf_perf_event_value___local *accum;
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diff.counter = after->counter - before->counter;
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diff.enabled = after->enabled - before->enabled;
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@@ -93,7 +99,7 @@ fexit_update_maps(u32 id, struct bpf_perf_event_value *after)
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SEC("fexit/XXX")
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int BPF_PROG(fexit_XXX)
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{
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- struct bpf_perf_event_value readings[MAX_NUM_MATRICS];
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+ struct bpf_perf_event_value___local readings[MAX_NUM_MATRICS];
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u32 cpu = bpf_get_smp_processor_id();
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u32 i, zero = 0;
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int err;
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@@ -102,7 +108,8 @@ int BPF_PROG(fexit_XXX)
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/* read all events before updating the maps, to reduce error */
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for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) {
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err = bpf_perf_event_read_value(&events, cpu + i * num_cpu,
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- readings + i, sizeof(*readings));
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+ (void *)(readings + i),
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+ sizeof(*readings));
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if (err)
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return 0;
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}
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--
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2.40.0
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