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Subject[PATCH 17/29] perf bpf: Fix synthesized PERF_RECORD_KSYMBOL/BPF_EVENT
Date
From: Song Liu <songliubraving@fb.com>

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>
---
tools/perf/util/bpf-event.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 01e1dc1bb7fb..796ef793f4ce 100644
--- 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) {
--
2.20.1
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