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Message-ID: <CAM9d7cjmmx2GQ7QQj3wBe1KkqgVNzoYbMuLeasVUWuZeLWUE9A@mail.gmail.com>
Date: Tue, 27 Jun 2023 08:35:44 -0700
From: Namhyung Kim <namhyung@...il.com>
To: Thomas Richter <tmricht@...ux.ibm.com>
Cc: linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
acme@...nel.org, irogers@...gle.com, hca@...ux.ibm.com,
svens@...ux.ibm.com, gor@...ux.ibm.com, sumanthk@...ux.ibm.com
Subject: Re: [PATCH] perf/test: perf test case Daemon operations dumps core
Hello,
On Tue, Jun 27, 2023 at 2:39 AM Thomas Richter <tmricht@...ux.ibm.com> wrote:
>
> The perf test case Daemon operations dumps core all the time.
> I narrowed it down to this invocation:
Jiri sent the same fix already. I'll add your Reported-by, ok?
https://lore.kernel.org/all/20230626201606.2514679-1-jolsa@kernel.org/
Thanks,
Namhyung
>
> Segmentation fault (core dumped)
> ....
> (gdb) where
> at builtin-daemon.c:1527
> argv=0x3ffe66f9630) at perf.c:323
> at perf.c:377
> at perf.c:421
> (gdb)
>
> Normally this goes unnoticed, the core dumps are only shown in
> verbose mode and when core dump generation is enabled on fedora 38:
>
> # ./perf test daemon
> 80: daemon operations : Ok
> # ll core*
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4586
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4688
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4812
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4857
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4893
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4933
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4947
> -rw------- 1 root root 3551232 Jun 27 10:08 core.4949
> # ./perf test -v daemon
> 80: daemon operations :
> --- start ---
> test child forked, pid 4974
> test daemon list
> ./tests/shell/daemon.sh: line 133: 4980 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> test daemon reconfig
> ./tests/shell/daemon.sh: line 133: 5082 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> test daemon stop
> ./tests/shell/daemon.sh: line 133: 5206 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> test daemon signal
> ./tests/shell/daemon.sh: line 133: 5250 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> signal 12 sent to session 'test [5252]'
> signal 12 sent to session 'test [5252]'
> test daemon ping
> ./tests/shell/daemon.sh: line 133: 5286 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> test daemon lock
> ./tests/shell/daemon.sh: line 133: 5326 Segmentation fault \
> (core dumped) perf daemon start --config ${config}
> test child finished with 0
> ---- end ----
> daemon operations: Ok
> # ll core*|wc -l
> 16
> #
>
> The root cause is in function cmd_daemon():
>
> argc = parse_options(argc, argv, daemon_options, daemon_usage,
> PARSE_OPT_STOP_AT_NON_OPTION);
>
> if (argc) {
> if (!strcmp(argv[0], "start"))
> ret = __cmd_start(&__daemon, daemon_options, argc,
> argv);
> if (!strcmp(argv[0], "signal"))
> ^^^^^^^
> Parameter argv[0] is set to NULL in function __cmd_start() and the
> next strcmp() accesses a NULL pointer.
>
> Output after:
>
> # ./perf daemon start --config /tmp/perf-daemon-config
> #
> # ./perf test -v daemon
> 80: daemon operations :
> --- start ---
> test child forked, pid 6517
> test daemon list
> test daemon reconfig
> test daemon stop
> test daemon signal
> signal 12 sent to session 'test [6780]'
> signal 12 sent to session 'test [6780]'
> test daemon ping
> test daemon lock
> test child finished with 0
> ---- end ----
> daemon operations: Ok
> #
>
> Fixes: 92294b906e6c ("perf daemon: Dynamically allocate path to perf")
>
> Signed-off-by: Thomas Richter <tmricht@...ux.ibm.com>
> ---
> tools/perf/builtin-daemon.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
> index f5674d824a40..83954af36753 100644
> --- a/tools/perf/builtin-daemon.c
> +++ b/tools/perf/builtin-daemon.c
> @@ -1524,7 +1524,7 @@ int cmd_daemon(int argc, const char **argv)
> if (argc) {
> if (!strcmp(argv[0], "start"))
> ret = __cmd_start(&__daemon, daemon_options, argc, argv);
> - if (!strcmp(argv[0], "signal"))
> + else if (!strcmp(argv[0], "signal"))
> ret = __cmd_signal(&__daemon, daemon_options, argc, argv);
> else if (!strcmp(argv[0], "stop"))
> ret = __cmd_stop(&__daemon, daemon_options, argc, argv);
> --
> 2.41.0
>
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