linux/tools/perf
Adrian Hunter ec183d22cc perf tools: tracepoint_error() can receive e=NULL, robustify it
Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  #1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  #2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  #3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  #4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  #5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  #6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  #7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  #8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  #9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Tong Zhang <ztong@vt.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: 196581717d ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/1453809921-24596-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-02-01 11:51:15 -03:00
..
Documentation perf tools: Add more usage tips 2016-01-12 12:42:07 -03:00
arch perf tests: Remove wrong semicolon in while loop in CQM test 2016-01-26 11:14:06 -03:00
bench perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
config perf build: Introduce FEATURES_DUMP make variable 2016-01-15 16:32:00 -03:00
python perf python: Support the PERF_RECORD_SWITCH event 2015-10-07 19:41:50 -03:00
scripts perf script: Add stat-cpi.py script 2016-01-06 20:11:16 -03:00
tests perf build: Pass O option to kernel makefile in build-test 2016-01-15 16:32:00 -03:00
trace/strace/groups perf trace: Add read/write to the file group 2015-09-04 13:22:06 -03:00
ui perf annotate browser: Fix behaviour of Shift-Tab with nothing focussed 2016-01-26 11:14:25 -03:00
util perf tools: tracepoint_error() can receive e=NULL, robustify it 2016-02-01 11:51:15 -03:00
.gitignore perf tools: Add Intel PT instruction decoder 2015-08-17 11:11:36 -03:00
Build perf tools: Set and pass DOCDIR to builtin-report.c 2016-01-12 12:42:07 -03:00
CREDITS
MANIFEST perf tools: Add missing sources to perf's MANIFEST 2016-01-11 12:09:25 -03:00
Makefile perf tools: Allow shuffling the build tests 2015-11-05 11:39:54 -03:00
Makefile.perf perf build: Introduce FEATURES_DUMP make variable 2016-01-15 16:32:00 -03:00
builtin-annotate.c perf tools: Pass evlist to setup_sorting() 2016-01-06 20:11:11 -03:00
builtin-bench.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-buildid-cache.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-buildid-list.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-config.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-data.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-diff.c perf diff: Use perf_hpp__register_sort_field interface 2016-01-08 12:59:30 -03:00
builtin-evlist.c perf evlist: Add --trace-fields option to show trace fields 2016-01-08 14:23:02 -03:00
builtin-help.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-inject.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-kmem.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-kvm.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-list.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-lock.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-mem.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-probe.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-record.c perf record: Add --buildid-all option 2016-01-12 12:42:07 -03:00
builtin-report.c perf tools: Fallback to srcdir/Documentation/tips.txt 2016-01-12 12:42:08 -03:00
builtin-sched.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-script.c perf script: Align event name properly 2016-01-08 12:57:26 -03:00
builtin-stat.c perf stat: Fix recort_usage typo 2016-01-12 11:13:52 -03:00
builtin-timechart.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-top.c perf report/top: Add --raw-trace option 2016-01-06 20:11:12 -03:00
builtin-trace.c perf subcmd: Create subcmd library 2015-12-17 14:27:14 -03:00
builtin-version.c perf tools: Move cmd_version() to builtin-version.c 2015-12-09 13:42:03 -03:00
builtin.h perf tools: Add 'perf config' command 2015-11-23 18:31:24 -03:00
command-list.txt perf tools: Do not show trace command if it's not compiled in 2016-01-08 12:46:17 -03:00
design.txt perf tools: Update some code references in design.txt 2014-03-18 18:17:06 -03:00
perf-archive.sh perf archive: Make 'f' the last parameter for tar 2012-09-17 13:10:42 -03:00
perf-completion.sh perf tools: Avoid confusion with preloaded bash function for perf bash completion 2015-03-19 13:53:27 -03:00
perf-read-vdso.c perf tools: Build programs to copy 32-bit compatibility 2014-10-29 10:32:48 -02:00
perf-sys.h perf tools: Move generic barriers out of perf-sys.h 2015-05-08 16:05:08 -03:00
perf-with-kcore.sh perf tools: Fix perf-with-kcore handling of arguments containing spaces 2015-08-06 16:48:27 -03:00
perf.c perf report: Show random usage tip on the help line 2016-01-08 13:15:46 -03:00
perf.h perf record: Add ability to name registers to record 2015-08-31 18:01:33 -03:00