perf bpf: Fix synthesized PERF_RECORD_KSYMBOL/BPF_EVENT

Added missing machine->id_hdr_size to event->header.size. Also fixed
size of PERF_RECORD_KSYMBOL by removing extra bytes for name.

Committer notes:

We need to malloc that extra machine->id_hdr_size at the start of
perf_event__synthesize_bpf_events() and also need to cast the event to
(void *) otherwise we segfault, fix it.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Suggested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Fixes: 7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs")
Link: http://lkml.kernel.org/r/20190122210218.358664-1-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 01e1dc1bb7fb38b5c536e29d14476b40e1ef7b5e..796ef793f4cea05695b8f20569f528d5e08a3e37 100644 (file)
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -7,6 +7,7 @@
 #include "bpf-event.h"
 #include "debug.h"
 #include "symbol.h"
+#include "machine.h"
 
 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
 
@@ -149,7 +150,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
                *ksymbol_event = (struct ksymbol_event){
                        .header = {
                                .type = PERF_RECORD_KSYMBOL,
-                               .size = sizeof(struct ksymbol_event),
+                               .size = offsetof(struct ksymbol_event, name),
                        },
                        .addr = prog_addrs[i],
                        .len = prog_lens[i],
@@ -178,6 +179,9 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
 
                ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
                                                         sizeof(u64));
+
+               memset((void *)event + event->header.size, 0, machine->id_hdr_size);
+               event->header.size += machine->id_hdr_size;
                err = perf_tool__process_synth_event(tool, event,
                                                     machine, process);
        }
@@ -194,6 +198,8 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
                        .id = info.id,
                };
                memcpy(bpf_event->tag, prog_tags[i], BPF_TAG_SIZE);
+               memset((void *)event + event->header.size, 0, machine->id_hdr_size);
+               event->header.size += machine->id_hdr_size;
                err = perf_tool__process_synth_event(tool, event,
                                                     machine, process);
        }
@@ -217,7 +223,7 @@ int perf_event__synthesize_bpf_events(struct perf_tool *tool,
        int err;
        int fd;
 
-       event = malloc(sizeof(event->bpf_event) + KSYM_NAME_LEN);
+       event = malloc(sizeof(event->bpf_event) + KSYM_NAME_LEN + machine->id_hdr_size);
        if (!event)
                return -1;
        while (true) {