* [PATCH v2] perf script: perf script tests fails with segfault
@ 2025-04-21 9:25 Aditya Bodkhe
2025-04-22 7:01 ` Adrian Hunter
2025-04-22 12:19 ` Disha Goel
0 siblings, 2 replies; 3+ messages in thread
From: Aditya Bodkhe @ 2025-04-21 9:25 UTC (permalink / raw)
To: linux-perf-users; +Cc: Disha Goel, Aditya Bodkhe, Adrian Hunter
perf script: pert script tests fails with segmentation fault as below:
92: perf script tests:
--- start ---
test child forked, pid 103769
DB test
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB /tmp/perf-test-script.7rbftEpOzX/perf.data (9 samples) ]
/usr/libexec/perf-core/tests/shell/script.sh: line 35: 103780 Segmentation fault (core dumped) perf script -i "${perfdatafile}" -s "${db_test}"
--- Cleaning up ---
---- end(-1) ----
92: perf script tests : FAILED!
Backtrace pointed to :
#0 0x0000000010247dd0 in maps.machine ()
#1 0x00000000101d178c in db_export.sample ()
#2 0x00000000103412c8 in python_process_event ()
#3 0x000000001004eb28 in process_sample_event ()
#4 0x000000001024fcd0 in machines.deliver_event ()
#5 0x000000001025005c in perf_session.deliver_event ()
#6 0x00000000102568b0 in __ordered_events__flush.part.0 ()
#7 0x0000000010251618 in perf_session.process_events ()
#8 0x0000000010053620 in cmd_script ()
#9 0x00000000100b5a28 in run_builtin ()
#10 0x00000000100b5f94 in handle_internal_command ()
#11 0x0000000010011114 in main ()
Further investigation reveals that this occurs in the `perf script tests`,
because it uses `db_test.py` script. This script sets `perf_db_export_mode = True`.
With `perf_db_export_mode` enabled, if a sample originates from a hypervisor,
perf doesn't set maps for "[H]" sample in the code. Consequently, `al->maps` remains NULL
when `maps__machine(al->maps)` is called from `db_export__sample`.
As al->maps can be NULL in case of Hypervisor samples , use thread->maps
because even for Hypervisor sample, machine should exist.
If we don't have machine for some reason, return -1 to avoid segmentation fault.
Reported-by: Disha Goel <disgoel@linux.ibm.com>
Signed-off-by: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
---
Changelog:
v1 -> v2:
The below patch contains changes suggested by Adrian Hunter<adrian.hunter@intel.com> to handle the segmentation fault ,
as well as initialisation of al.thread
tools/perf/util/db-export.c | 11 ++++++++---
.../perf/util/scripting-engines/trace-event-python.c | 2 +-
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 50f916374d87..8f52e8cefcf3 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -181,7 +181,7 @@ static int db_ids_from_al(struct db_export *dbe, struct addr_location *al,
if (al->map) {
struct dso *dso = map__dso(al->map);
- err = db_export__dso(dbe, dso, maps__machine(al->maps));
+ err = db_export__dso(dbe, dso, maps__machine(thread__maps(al->thread)));
if (err)
return err;
*dso_db_id = dso__db_id(dso);
@@ -256,6 +256,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
al.map = map__get(node->ms.map);
al.maps = maps__get(thread__maps(thread));
al.addr = node->ip;
+ al.thread = thread__get(thread);
if (al.map && !al.sym)
al.sym = dso__find_symbol(map__dso(al.map), al.addr);
@@ -358,14 +359,18 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
};
struct thread *main_thread;
struct comm *comm = NULL;
- struct machine *machine;
+ struct machine *machine = NULL;
int err;
+ if (thread__maps(thread))
+ machine = maps__machine(thread__maps(thread));
+ if (!machine)
+ return -1;
+
err = db_export__evsel(dbe, evsel);
if (err)
return err;
- machine = maps__machine(al->maps);
err = db_export__machine(dbe, machine);
if (err)
return err;
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 520729e78965..00f2c6c5114d 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -1306,7 +1306,7 @@ static void python_export_sample_table(struct db_export *dbe,
tuple_set_d64(t, 0, es->db_id);
tuple_set_d64(t, 1, es->evsel->db_id);
- tuple_set_d64(t, 2, maps__machine(es->al->maps)->db_id);
+ tuple_set_d64(t, 2, maps__machine(thread__maps(es->al->thread))->db_id);
tuple_set_d64(t, 3, thread__db_id(es->al->thread));
tuple_set_d64(t, 4, es->comm_db_id);
tuple_set_d64(t, 5, es->dso_db_id);
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] perf script: perf script tests fails with segfault
2025-04-21 9:25 [PATCH v2] perf script: perf script tests fails with segfault Aditya Bodkhe
@ 2025-04-22 7:01 ` Adrian Hunter
2025-04-22 12:19 ` Disha Goel
1 sibling, 0 replies; 3+ messages in thread
From: Adrian Hunter @ 2025-04-22 7:01 UTC (permalink / raw)
To: Aditya Bodkhe, linux-perf-users; +Cc: Disha Goel, Aditya Bodkhe
On 21/04/25 12:25, Aditya Bodkhe wrote:
> perf script: pert script tests fails with segmentation fault as below:
>
> 92: perf script tests:
> --- start ---
Using --- here and below messes up the commit message
e.g. when applied with git am
Needs to be prefixed by at least 1 space
> test child forked, pid 103769
> DB test
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.012 MB /tmp/perf-test-script.7rbftEpOzX/perf.data (9 samples) ]
> /usr/libexec/perf-core/tests/shell/script.sh: line 35: 103780 Segmentation fault (core dumped) perf script -i "${perfdatafile}" -s "${db_test}"
> --- Cleaning up ---
Ditto
> ---- end(-1) ----
Ditto
> 92: perf script tests : FAILED!
>
> Backtrace pointed to :
> #0 0x0000000010247dd0 in maps.machine ()
> #1 0x00000000101d178c in db_export.sample ()
> #2 0x00000000103412c8 in python_process_event ()
> #3 0x000000001004eb28 in process_sample_event ()
> #4 0x000000001024fcd0 in machines.deliver_event ()
> #5 0x000000001025005c in perf_session.deliver_event ()
> #6 0x00000000102568b0 in __ordered_events__flush.part.0 ()
> #7 0x0000000010251618 in perf_session.process_events ()
> #8 0x0000000010053620 in cmd_script ()
> #9 0x00000000100b5a28 in run_builtin ()
> #10 0x00000000100b5f94 in handle_internal_command ()
> #11 0x0000000010011114 in main ()
>
> Further investigation reveals that this occurs in the `perf script tests`,
> because it uses `db_test.py` script. This script sets `perf_db_export_mode = True`.
>
> With `perf_db_export_mode` enabled, if a sample originates from a hypervisor,
> perf doesn't set maps for "[H]" sample in the code. Consequently, `al->maps` remains NULL
> when `maps__machine(al->maps)` is called from `db_export__sample`.
>
> As al->maps can be NULL in case of Hypervisor samples , use thread->maps
> because even for Hypervisor sample, machine should exist.
> If we don't have machine for some reason, return -1 to avoid segmentation fault.
>
> Reported-by: Disha Goel <disgoel@linux.ibm.com>
> Signed-off-by: Aditya Bodkhe <aditya.b1@linux.ibm.com>
> Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
With --- fixes:
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
> Changelog:
> v1 -> v2:
> The below patch contains changes suggested by Adrian Hunter<adrian.hunter@intel.com> to handle the segmentation fault ,
> as well as initialisation of al.thread
>
> tools/perf/util/db-export.c | 11 ++++++++---
> .../perf/util/scripting-engines/trace-event-python.c | 2 +-
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
> index 50f916374d87..8f52e8cefcf3 100644
> --- a/tools/perf/util/db-export.c
> +++ b/tools/perf/util/db-export.c
> @@ -181,7 +181,7 @@ static int db_ids_from_al(struct db_export *dbe, struct addr_location *al,
> if (al->map) {
> struct dso *dso = map__dso(al->map);
>
> - err = db_export__dso(dbe, dso, maps__machine(al->maps));
> + err = db_export__dso(dbe, dso, maps__machine(thread__maps(al->thread)));
> if (err)
> return err;
> *dso_db_id = dso__db_id(dso);
> @@ -256,6 +256,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
> al.map = map__get(node->ms.map);
> al.maps = maps__get(thread__maps(thread));
> al.addr = node->ip;
> + al.thread = thread__get(thread);
>
> if (al.map && !al.sym)
> al.sym = dso__find_symbol(map__dso(al.map), al.addr);
> @@ -358,14 +359,18 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
> };
> struct thread *main_thread;
> struct comm *comm = NULL;
> - struct machine *machine;
> + struct machine *machine = NULL;
> int err;
>
> + if (thread__maps(thread))
> + machine = maps__machine(thread__maps(thread));
> + if (!machine)
> + return -1;
> +
> err = db_export__evsel(dbe, evsel);
> if (err)
> return err;
>
> - machine = maps__machine(al->maps);
> err = db_export__machine(dbe, machine);
> if (err)
> return err;
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index 520729e78965..00f2c6c5114d 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -1306,7 +1306,7 @@ static void python_export_sample_table(struct db_export *dbe,
>
> tuple_set_d64(t, 0, es->db_id);
> tuple_set_d64(t, 1, es->evsel->db_id);
> - tuple_set_d64(t, 2, maps__machine(es->al->maps)->db_id);
> + tuple_set_d64(t, 2, maps__machine(thread__maps(es->al->thread))->db_id);
> tuple_set_d64(t, 3, thread__db_id(es->al->thread));
> tuple_set_d64(t, 4, es->comm_db_id);
> tuple_set_d64(t, 5, es->dso_db_id);
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] perf script: perf script tests fails with segfault
2025-04-21 9:25 [PATCH v2] perf script: perf script tests fails with segfault Aditya Bodkhe
2025-04-22 7:01 ` Adrian Hunter
@ 2025-04-22 12:19 ` Disha Goel
1 sibling, 0 replies; 3+ messages in thread
From: Disha Goel @ 2025-04-22 12:19 UTC (permalink / raw)
To: Aditya Bodkhe, linux-perf-users; +Cc: Aditya Bodkhe, Adrian Hunter
On 21/04/25 2:55 pm, Aditya Bodkhe wrote:
> perf script: pert script tests fails with segmentation fault as below:
>
> 92: perf script tests:
> --- start ---
> test child forked, pid 103769
> DB test
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.012 MB /tmp/perf-test-script.7rbftEpOzX/perf.data (9 samples) ]
> /usr/libexec/perf-core/tests/shell/script.sh: line 35: 103780 Segmentation fault (core dumped) perf script -i "${perfdatafile}" -s "${db_test}"
> --- Cleaning up ---
> ---- end(-1) ----
> 92: perf script tests : FAILED!
>
> Backtrace pointed to :
> #0 0x0000000010247dd0 in maps.machine ()
> #1 0x00000000101d178c in db_export.sample ()
> #2 0x00000000103412c8 in python_process_event ()
> #3 0x000000001004eb28 in process_sample_event ()
> #4 0x000000001024fcd0 in machines.deliver_event ()
> #5 0x000000001025005c in perf_session.deliver_event ()
> #6 0x00000000102568b0 in __ordered_events__flush.part.0 ()
> #7 0x0000000010251618 in perf_session.process_events ()
> #8 0x0000000010053620 in cmd_script ()
> #9 0x00000000100b5a28 in run_builtin ()
> #10 0x00000000100b5f94 in handle_internal_command ()
> #11 0x0000000010011114 in main ()
>
> Further investigation reveals that this occurs in the `perf script tests`,
> because it uses `db_test.py` script. This script sets `perf_db_export_mode = True`.
>
> With `perf_db_export_mode` enabled, if a sample originates from a hypervisor,
> perf doesn't set maps for "[H]" sample in the code. Consequently, `al->maps` remains NULL
> when `maps__machine(al->maps)` is called from `db_export__sample`.
>
> As al->maps can be NULL in case of Hypervisor samples , use thread->maps
> because even for Hypervisor sample, machine should exist.
> If we don't have machine for some reason, return -1 to avoid segmentation fault.
>
> Reported-by: Disha Goel <disgoel@linux.ibm.com>
> Signed-off-by: Aditya Bodkhe <aditya.b1@linux.ibm.com>
> Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
I have tested the patch on PowerPC, it fixes the reported issue and test
passes.
Tested-by: Disha Goel <disgoel@linux.ibm.com>
> ---
> Changelog:
> v1 -> v2:
> The below patch contains changes suggested by Adrian Hunter<adrian.hunter@intel.com> to handle the segmentation fault ,
> as well as initialisation of al.thread
>
> tools/perf/util/db-export.c | 11 ++++++++---
> .../perf/util/scripting-engines/trace-event-python.c | 2 +-
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
> index 50f916374d87..8f52e8cefcf3 100644
> --- a/tools/perf/util/db-export.c
> +++ b/tools/perf/util/db-export.c
> @@ -181,7 +181,7 @@ static int db_ids_from_al(struct db_export *dbe, struct addr_location *al,
> if (al->map) {
> struct dso *dso = map__dso(al->map);
>
> - err = db_export__dso(dbe, dso, maps__machine(al->maps));
> + err = db_export__dso(dbe, dso, maps__machine(thread__maps(al->thread)));
> if (err)
> return err;
> *dso_db_id = dso__db_id(dso);
> @@ -256,6 +256,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
> al.map = map__get(node->ms.map);
> al.maps = maps__get(thread__maps(thread));
> al.addr = node->ip;
> + al.thread = thread__get(thread);
>
> if (al.map && !al.sym)
> al.sym = dso__find_symbol(map__dso(al.map), al.addr);
> @@ -358,14 +359,18 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
> };
> struct thread *main_thread;
> struct comm *comm = NULL;
> - struct machine *machine;
> + struct machine *machine = NULL;
> int err;
>
> + if (thread__maps(thread))
> + machine = maps__machine(thread__maps(thread));
> + if (!machine)
> + return -1;
> +
> err = db_export__evsel(dbe, evsel);
> if (err)
> return err;
>
> - machine = maps__machine(al->maps);
> err = db_export__machine(dbe, machine);
> if (err)
> return err;
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index 520729e78965..00f2c6c5114d 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -1306,7 +1306,7 @@ static void python_export_sample_table(struct db_export *dbe,
>
> tuple_set_d64(t, 0, es->db_id);
> tuple_set_d64(t, 1, es->evsel->db_id);
> - tuple_set_d64(t, 2, maps__machine(es->al->maps)->db_id);
> + tuple_set_d64(t, 2, maps__machine(thread__maps(es->al->thread))->db_id);
> tuple_set_d64(t, 3, thread__db_id(es->al->thread));
> tuple_set_d64(t, 4, es->comm_db_id);
> tuple_set_d64(t, 5, es->dso_db_id);
> --
> 2.43.0
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-04-21 9:25 [PATCH v2] perf script: perf script tests fails with segfault Aditya Bodkhe
2025-04-22 7:01 ` Adrian Hunter
2025-04-22 12:19 ` Disha Goel
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