I'll try and continue later, but if you guys can take a look... The first call in that loop:
while ((event = trace_find_next_event(pevent, event))) works and the event is valid, one of the sched: tracepoints, but then the next call returns this: struct tep_event *trace_find_next_event(struct tep_handle *pevent, struct tep_event *event) { static int idx; int events_count; struct tep_event *all_events; all_events = tep_get_first_event(pevent); events_count = tep_get_events_count(pevent); if (!pevent || !all_events || events_count < 1) return NULL; if (!event) { idx = 0; return all_events; } if (idx < events_count && event == (all_events + idx)) { idx++; if (idx == events_count) return NULL; return (all_events + idx); } for (idx = 1; idx < events_count; idx++) { if (event == (all_events + (idx - 1))) return (all_events + idx); } return NULL; } Oh, static int idx, oops, anyway, the all_events + idx returned for the second call to trace_find_next_event() fails, in a hurry now, will get back to this later. - Arnaldo [root@quaco ~]# perf record -e sched:* sleep 1 [ perf record: Woken up 33 times to write data ] [ perf record: Captured and wrote 0.030 MB perf.data (8 samples) ] [root@quaco ~]# perf script -g python Segmentation fault (core dumped) [root@quaco ~]# Bisected to: [acme@quaco perf]$ git bisect bad bb3dd7e7c4d5e024d607c0ec06c2a2fb9408cc99 is the first bad commit commit bb3dd7e7c4d5e024d607c0ec06c2a2fb9408cc99 Author: Tzvetomir Stoyanov <tstoya...@vmware.com> Date: Fri Oct 5 12:22:25 2018 -0400 tools lib traceevent, perf tools: Move struct tep_handler definition in a local header file As traceevent is going to be transferred into a proper library, its local data should be protected from the library users. This patch encapsulates struct tep_handler into a local header, not visible outside of the library. It implements also a bunch of new APIs, which library users can use to access tep_handler members. Signed-off-by: Tzvetomir Stoyanov <tstoya...@vmware.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: linux trace devel <linux-trace-de...@vger.kernel.org> Cc: tzvetomir stoyanov <tstoya...@vmware.com> Link: http://lkml.kernel.org/r/20181005122225.52215...@gandalf.local.home Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> :040000 040000 7a23aa486fd8ed255b681e6c959d6ab64d16f2f6 d95f601bb03b81bc04070b69635df40b62c70a1a M tools [acme@quaco perf]$ [root@quaco ~]# gdb perf GNU gdb (GDB) Fedora 8.3-6.fc30 Reading symbols from perf... (gdb) run script -g python Starting program: /root/bin/perf script -g python [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". [Detaching after fork from child process 10352] Program received signal SIGSEGV, Segmentation fault. 0x00007ffff76f55e5 in __strlen_avx2 () from /lib64/libc.so.6 Missing separate debuginfos, use: dnf debuginfo-install bzip2-libs-1.0.6-29.fc30.x86_64 elfutils-libelf-0.177-1.fc30.x86_64 elfutils-libs-0.177-1.fc30.x86_64 glib2-2.60.7-1.fc30.x86_64 libbabeltrace-1.5.6-2.fc30.x86_64 libcap-2.26-5.fc30.x86_64 libgcc-9.2.1-1.fc30.x86_64 libunwind-1.3.1-2.fc30.x86_64 libuuid-2.33.2-2.fc30.x86_64 libxcrypt-4.4.10-1.fc30.x86_64 libzstd-1.4.2-1.fc30.x86_64 numactl-libs-2.0.12-2.fc30.x86_64 pcre-8.43-2.fc30.x86_64 perl-libs-5.28.2-440.fc30.x86_64 popt-1.16-17.fc30.x86_64 slang-2.3.2-5.fc30.x86_64 xz-libs-5.2.4-5.fc30.x86_64 zlib-1.2.11-18.fc30.x86_64 (gdb) bt #0 0x00007ffff76f55e5 in __strlen_avx2 () from /lib64/libc.so.6 #1 0x00007ffff7601a1e in __vfprintf_internal () from /lib64/libc.so.6 #2 0x00007ffff75ec2ba in fprintf () from /lib64/libc.so.6 #3 0x00000000005ec8db in python_generate_script (pevent=0xbedb10, outfile=0x71f761 "perf-script") at util/scripting-engines/trace-event-python.c:1739 #4 0x000000000046e94a in cmd_script (argc=0, argv=0x7fffffffd680) at builtin-script.c:3848 #5 0x00000000004e0d86 in run_builtin (p=0xa3d238 <commands+408>, argc=3, argv=0x7fffffffd680) at perf.c:312 #6 0x00000000004e0ff3 in handle_internal_command (argc=3, argv=0x7fffffffd680) at perf.c:364 #7 0x00000000004e113a in run_argv (argcp=0x7fffffffd4dc, argv=0x7fffffffd4d0) at perf.c:408 #8 0x00000000004e1506 in main (argc=3, argv=0x7fffffffd680) at perf.c:538 (gdb) fr 3 #3 0x00000000005ec8db in python_generate_script (pevent=0xbedb10, outfile=0x71f761 "perf-script") at util/scripting-engines/trace-event-python.c:1739 1739 fprintf(ofp, "def %s__%s(", event->system, event->name); (gdb) p event $1 = (struct tep_event *) 0xbfa298 (gdb) p *event $2 = {tep = 0x31, name = 0x61775f6465686373 <error: Cannot access memory at address 0x61775f6465686373>, id = 1767859563, flags = 1600482404, format = {nr_common = 1752459639, nr_fields = 1601467759, common_fields = 0x6e6f6d6d00697069, fields = 0x93b7367616c665f}, print_fmt = {format = 0x21 <error: Cannot access memory at address 0x21>, args = 0x64656e6769736e75}, system = 0x74726f687320 <error: Cannot access memory at address 0x74726f687320>, handler = 0x656966090a3b303a, context = 0x51} (gdb) list -20 1714 fprintf(ofp, "# in the format files. Those fields not available as " 1715 "handler params can\n"); 1716 1717 fprintf(ofp, "# be retrieved using Python functions of the form " 1718 "common_*(context).\n"); 1719 1720 fprintf(ofp, "# See the perf-script-python Documentation for the list " 1721 "of available functions.\n\n"); 1722 1723 fprintf(ofp, "from __future__ import print_function\n\n"); (gdb) 1724 fprintf(ofp, "import os\n"); 1725 fprintf(ofp, "import sys\n\n"); 1726 1727 fprintf(ofp, "sys.path.append(os.environ['PERF_EXEC_PATH'] + \\\n"); 1728 fprintf(ofp, "\t'/scripts/python/Perf-Trace-Util/lib/Perf/Trace')\n"); 1729 fprintf(ofp, "\nfrom perf_trace_context import *\n"); 1730 fprintf(ofp, "from Core import *\n\n\n"); 1731 1732 fprintf(ofp, "def trace_begin():\n"); 1733 fprintf(ofp, "\tprint(\"in trace_begin\")\n\n"); (gdb) 1734 1735 fprintf(ofp, "def trace_end():\n"); 1736 fprintf(ofp, "\tprint(\"in trace_end\")\n\n"); 1737 1738 while ((event = trace_find_next_event(pevent, event))) { 1739 fprintf(ofp, "def %s__%s(", event->system, event->name); 1740 fprintf(ofp, "event_name, "); 1741 fprintf(ofp, "context, "); 1742 fprintf(ofp, "common_cpu,\n"); 1743 fprintf(ofp, "\tcommon_secs, "); - Arnaldo