[PATCH v1 1/4] perf record: Delete session after stopping sideband thread

[Ian Rogers]

The session has a header in it which contains a perf env with
bpf_progs. The bpf_progs are accessed by the sideband thread and so
the sideband thread must be stopped before the session is deleted, to
avoid a use after free.  This error was detected by AddressSanitizer
in the following:

```
==2054673==ERROR: AddressSanitizer: heap-use-after-free on address 0x61d000161e00 at pc 0x55769289de54 bp 0x7f9df36d4ab0 sp 0x7f9df36d4aa8
READ of size 8 at 0x61d000161e00 thread T1
    #0 0x55769289de53 in __perf_env__insert_bpf_prog_info util/env.c:42
    #1 0x55769289dbb1 in perf_env__insert_bpf_prog_info util/env.c:29
    #2 0x557692bbae29 in perf_env__add_bpf_info util/bpf-event.c:483
    #3 0x557692bbb01a in bpf_event__sb_cb util/bpf-event.c:512
    #4 0x5576928b75f4 in perf_evlist__poll_thread util/sideband_evlist.c:68
    #5 0x7f9df96a63eb in start_thread nptl/pthread_create.c:444
    #6 0x7f9df9726a4b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

0x61d000161e00 is located 384 bytes inside of 2136-byte region [0x61d000161c80,0x61d0001624d8)
freed by thread T0 here:
    #0 0x7f9dfa6d7288 in __interceptor_free libsanitizer/asan/asan_malloc_linux.cpp:52
    #1 0x557692978d50 in perf_session__delete util/session.c:319
    #2 0x557692673959 in __cmd_record tools/perf/builtin-record.c:2884
    #3 0x55769267a9f0 in cmd_record tools/perf/builtin-record.c:4259
    #4 0x55769286710c in run_builtin tools/perf/perf.c:349
    #5 0x557692867678 in handle_internal_command tools/perf/perf.c:402
    #6 0x557692867a40 in run_argv tools/perf/perf.c:446
    #7 0x557692867fae in main tools/perf/perf.c:562
    #8 0x7f9df96456c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
```

Fixes: 657ee5531903 ("perf evlist: Introduce side band thread")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/builtin-record.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 92ccca9574ca..32df34dda9cd 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2881,10 +2881,10 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	}
 #endif
 	zstd_fini(&session->zstd_data);
-	perf_session__delete(session);
-
 	if (!opts->no_bpf_event)
 		evlist__stop_sb_thread(rec->sb_evlist);
+
+	perf_session__delete(session);
 	return status;
 }
 
-- 
2.44.0.278.ge034bb2e1d-goog