From: Song Liu songliubraving@fb.com
bpf/btf write_* functions need ff->ph->env.
With this missing, pipe-mode (perf record -o -) would crash like:
Program terminated with signal SIGSEGV, Segmentation fault.
This patch assign proper ph value to ff.
Committer testing:
(gdb) run record -o - Starting program: /root/bin/perf record -o - PERFILE2 <SNIP start of perf.data headers> Thread 1 "perf" received signal SIGSEGV, Segmentation fault. __do_write_buf (size=4, buf=0x160, ff=0x7fffffff8f80) at util/header.c:126 126 memcpy(ff->buf + ff->offset, buf, size); (gdb) bt #0 __do_write_buf (size=4, buf=0x160, ff=0x7fffffff8f80) at util/header.c:126 #1 do_write (ff=ff@entry=0x7fffffff8f80, buf=buf@entry=0x160, size=4) at util/header.c:137 #2 0x00000000004eddba in write_bpf_prog_info (ff=0x7fffffff8f80, evlist=<optimized out>) at util/header.c:912 #3 0x00000000004f69d7 in perf_event__synthesize_features (tool=tool@entry=0x97cc00 <record>, session=session@entry=0x7fffe9c6d010, evlist=0x7fffe9cae010, process=process@entry=0x4435d0 <process_synthesized_event>) at util/header.c:3695 #4 0x0000000000443c79 in record__synthesize (tail=tail@entry=false, rec=0x97cc00 <record>) at builtin-record.c:1214 #5 0x0000000000444ec9 in __cmd_record (rec=0x97cc00 <record>, argv=<optimized out>, argc=0) at builtin-record.c:1435 #6 cmd_record (argc=0, argv=<optimized out>) at builtin-record.c:2450 #7 0x00000000004ae3e9 in run_builtin (p=p@entry=0x98e058 <commands+216>, argc=argc@entry=3, argv=0x7fffffffd670) at perf.c:304 #8 0x000000000042eded in handle_internal_command (argv=<optimized out>, argc=<optimized out>) at perf.c:356 #9 run_argv (argcp=<optimized out>, argv=<optimized out>) at perf.c:400 #10 main (argc=3, argv=<optimized out>) at perf.c:522 (gdb)
After the patch the SEGSEGV is gone.
Reported-by: David Carrillo Cisneros davidca@fb.com Signed-off-by: Song Liu songliubraving@fb.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: kernel-team@fb.com Cc: stable@vger.kernel.org # v5.1+ Fixes: 606f972b1361 ("perf bpf: Save bpf_prog_info information as headers to perf.data") Link: http://lkml.kernel.org/r/20190620010453.4118689-1-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com --- tools/perf/util/header.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 847ae51a524b..fb0aa661644b 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -3602,6 +3602,7 @@ int perf_event__synthesize_features(struct perf_tool *tool, return -ENOMEM;
ff.size = sz - sz_hdr; + ff.ph = &session->header;
for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) { if (!feat_ops[feat].synthesize) {