* Re: [PATCH] [PING] perf ftrace: Command fails on s390
2021-04-21 12:04 [PATCH] [PING] perf ftrace: Command fails on s390 Thomas Richter
@ 2021-04-21 19:53 ` Namhyung Kim
2021-04-23 13:40 ` Arnaldo Carvalho de Melo
2021-04-23 18:59 ` Arnaldo Carvalho de Melo
2 siblings, 0 replies; 4+ messages in thread
From: Namhyung Kim @ 2021-04-21 19:53 UTC (permalink / raw)
To: Thomas Richter
Cc: linux-kernel, linux-perf-users, Arnaldo Carvalho de Melo, svens,
gor, sumanthk, hca, Alexander Schmidt
Hello,
On Wed, Apr 21, 2021 at 10:03 PM Thomas Richter <tmricht@linux.ibm.com> wrote:
>
> Command 'perf ftrace -v -- ls' fails in s390 (at least 5.12.0rc6).
>
> The root cause is a missing pointer dereference which causes an
> array element address to be used as PID.
>
> Fix this by extracting the PID.
>
> Output before:
> # ./perf ftrace -v -- ls
> function_graph tracer is used
> write '-263732416' to tracing/set_ftrace_pid failed: Invalid argument
> failed to set ftrace pid
> #
>
> Output after:
> ./perf ftrace -v -- ls
> function_graph tracer is used
> # tracer: function_graph
> #
> # CPU DURATION FUNCTION CALLS
> # | | | | | | |
> 4) | rcu_read_lock_sched_held() {
> 4) 0.552 us | rcu_lockdep_current_cpu_online();
> 4) 6.124 us | }
>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> Reported-by: Alexander Schmidt <alexschm@de.ibm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> ---
> tools/perf/builtin-ftrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index d49448a1060c..87cb11a7a3ee 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -289,7 +289,7 @@ static int set_tracing_pid(struct perf_ftrace *ftrace)
>
> for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
> scnprintf(buf, sizeof(buf), "%d",
> - ftrace->evlist->core.threads->map[i]);
> + perf_thread_map__pid(ftrace->evlist->core.threads, i));
> if (append_tracing_file("set_ftrace_pid", buf) < 0)
> return -1;
> }
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] [PING] perf ftrace: Command fails on s390
2021-04-21 12:04 [PATCH] [PING] perf ftrace: Command fails on s390 Thomas Richter
2021-04-21 19:53 ` Namhyung Kim
@ 2021-04-23 13:40 ` Arnaldo Carvalho de Melo
2021-04-23 18:59 ` Arnaldo Carvalho de Melo
2 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-04-23 13:40 UTC (permalink / raw)
To: Thomas Richter
Cc: linux-kernel, linux-perf-users, svens, gor, sumanthk, hca,
Alexander Schmidt
Em Wed, Apr 21, 2021 at 02:04:00PM +0200, Thomas Richter escreveu:
> Command 'perf ftrace -v -- ls' fails in s390 (at least 5.12.0rc6).
>
> The root cause is a missing pointer dereference which causes an
> array element address to be used as PID.
>
> Fix this by extracting the PID.
Thanks, applied.
- Arnaldo
> Output before:
> # ./perf ftrace -v -- ls
> function_graph tracer is used
> write '-263732416' to tracing/set_ftrace_pid failed: Invalid argument
> failed to set ftrace pid
> #
>
> Output after:
> ./perf ftrace -v -- ls
> function_graph tracer is used
> # tracer: function_graph
> #
> # CPU DURATION FUNCTION CALLS
> # | | | | | | |
> 4) | rcu_read_lock_sched_held() {
> 4) 0.552 us | rcu_lockdep_current_cpu_online();
> 4) 6.124 us | }
>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> Reported-by: Alexander Schmidt <alexschm@de.ibm.com>
> ---
> tools/perf/builtin-ftrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index d49448a1060c..87cb11a7a3ee 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -289,7 +289,7 @@ static int set_tracing_pid(struct perf_ftrace *ftrace)
>
> for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
> scnprintf(buf, sizeof(buf), "%d",
> - ftrace->evlist->core.threads->map[i]);
> + perf_thread_map__pid(ftrace->evlist->core.threads, i));
> if (append_tracing_file("set_ftrace_pid", buf) < 0)
> return -1;
> }
> --
> 2.30.2
>
--
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] [PING] perf ftrace: Command fails on s390
2021-04-21 12:04 [PATCH] [PING] perf ftrace: Command fails on s390 Thomas Richter
2021-04-21 19:53 ` Namhyung Kim
2021-04-23 13:40 ` Arnaldo Carvalho de Melo
@ 2021-04-23 18:59 ` Arnaldo Carvalho de Melo
2 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-04-23 18:59 UTC (permalink / raw)
To: Thomas Richter
Cc: linux-kernel, linux-perf-users, svens, gor, sumanthk, hca,
Alexander Schmidt
Em Wed, Apr 21, 2021 at 02:04:00PM +0200, Thomas Richter escreveu:
> Command 'perf ftrace -v -- ls' fails in s390 (at least 5.12.0rc6).
>
> The root cause is a missing pointer dereference which causes an
> array element address to be used as PID.
Since you pinged on this one, and rightly so, please CC:
From the MAINTAINERS file:
PERFORMANCE EVENTS SUBSYSTEM
R: Jiri Olsa <jolsa@redhat.com>
R: Namhyung Kim <namhyung@kernel.org>
These reviewers that help me into getting patches processed.
Patch is processed now, good catch, I collected Namhyung's Acked-by.
Thanks,
- Arnaldo
> Fix this by extracting the PID.
>
> Output before:
> # ./perf ftrace -v -- ls
> function_graph tracer is used
> write '-263732416' to tracing/set_ftrace_pid failed: Invalid argument
> failed to set ftrace pid
> #
>
> Output after:
> ./perf ftrace -v -- ls
> function_graph tracer is used
> # tracer: function_graph
> #
> # CPU DURATION FUNCTION CALLS
> # | | | | | | |
> 4) | rcu_read_lock_sched_held() {
> 4) 0.552 us | rcu_lockdep_current_cpu_online();
> 4) 6.124 us | }
>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> Reported-by: Alexander Schmidt <alexschm@de.ibm.com>
> ---
> tools/perf/builtin-ftrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index d49448a1060c..87cb11a7a3ee 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -289,7 +289,7 @@ static int set_tracing_pid(struct perf_ftrace *ftrace)
>
> for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
> scnprintf(buf, sizeof(buf), "%d",
> - ftrace->evlist->core.threads->map[i]);
> + perf_thread_map__pid(ftrace->evlist->core.threads, i));
> if (append_tracing_file("set_ftrace_pid", buf) < 0)
> return -1;
> }
> --
> 2.30.2
>
--
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread