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authorTaeung Song <treeze.taeung@gmail.com>2016-02-26 00:12:59 +0900
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-02-25 12:54:20 -0300
commit8579aca3f9a8f890d6d94ccaed7cf5fd54a0c3bd (patch)
treef97e340ce9396e4281b2afd7396b88e970e414e9 /tools/perf/util/scripting-engines
parentbb109acc4adeae425147ca87b84d312ea40f24f1 (diff)
downloadop-kernel-dev-8579aca3f9a8f890d6d94ccaed7cf5fd54a0c3bd.zip
op-kernel-dev-8579aca3f9a8f890d6d94ccaed7cf5fd54a0c3bd.tar.gz
perf script: Exception handling when the print fmt is empty
After collecting samples for events 'syscalls:', perf-script with python script doesn't occasionally work generating a segmentation fault. The reason is that the print fmt is empty and a value of event->print_fmt.args is NULL, so dereferencing the null pointer results in a segmentation fault i.e.: # perf record -e syscalls:* # perf script -g python # perf script -s perf-script.py in trace_begin syscalls__sys_enter_brk 3 79841.832099154 3777 test.sh syscall_nr=12, brk=0 ... (omitted) ... Segmentation fault (core dumped) For example, a format of sys_enter_getuid() hasn't print fmt as below. # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_getuid/format name: sys_enter_getuid ID: 188 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:int syscall_nr; offset:8; size:4; signed:1; print fmt: "" So add exception handling to avoid this problem. Signed-off-by: Taeung Song <treeze.taeung@gmail.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1456413179-12331-1-git-send-email-treeze.taeung@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/scripting-engines')
-rw-r--r--tools/perf/util/scripting-engines/trace-event-perl.c3
-rw-r--r--tools/perf/util/scripting-engines/trace-event-python.c3
2 files changed, 6 insertions, 0 deletions
diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
index 544509c..b3aabc0 100644
--- a/tools/perf/util/scripting-engines/trace-event-perl.c
+++ b/tools/perf/util/scripting-engines/trace-event-perl.c
@@ -187,6 +187,9 @@ static void define_event_symbols(struct event_format *event,
const char *ev_name,
struct print_arg *args)
{
+ if (args == NULL)
+ return;
+
switch (args->type) {
case PRINT_NULL:
break;
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index d72fafc..309d90f 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -205,6 +205,9 @@ static void define_event_symbols(struct event_format *event,
const char *ev_name,
struct print_arg *args)
{
+ if (args == NULL)
+ return;
+
switch (args->type) {
case PRINT_NULL:
break;
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