Messages in this thread | | | From | Namhyung Kim <> | Date | Tue, 1 Apr 2014 07:21:44 +0000 | Subject | Re: [PATCH] perf probe: Fix --line option behavior |
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Hi Masami,
(Also adding Jiri in CC and changing email of acme)
On Tue, Apr 1, 2014 at 5:01 AM, Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote: > (2014/04/01 13:47), Namhyung Kim wrote: >> The commit 5a62257a3ddd1 ("perf probe: Replace line_list with >> intlist") replaced line_list to intlist but it has a problem that if a >> same line was added again, it'd return -EEXIST rather than 1. > > Ah, right! that's a different behavior. > >> Since line_range_walk_cb() only checks the result being negative, it >> resulted in failure or segfault sometimes. > > Could you give me an example input of the segfault? I'd like to trace > it down.
Just used current acme/perf/core.
$ git log -1 commit 28b5724a61cc9d84f2cbef6675e8a85ae4b1bc57 Author: Arnaldo Carvalho de Melo <acme@redhat.com> Date: Thu Mar 27 17:36:14 2014 -0300
MAINTAINERS: Change e-mail to kernel.org one
Leaving ghostprotocols.net for old networking stuff.
...
$ perf --version perf version 3.14.rc6.g28b572
$ perf probe -x ./perf -v -L map__load Open Debuginfo file: /home/namhyung/project/linux/tools/perf/perf fname: util/map.c, lineno:153 New line range: 153 to 2147483647 path: (null) Segmentation fault (core dumped)
It seems like find_line_range_by_line() called for multiple times, line_range_walk_cb returns 0 at first but as line_range_add_line() returns -EEXIST, it freed lr->path and __show_line_range() ended up accessing to NULL path.
(gdb) bt #0 get_real_path (new_path=0x839ff8 <params+9272>, comp_dir=0x1f994f0 "/home/namhyung/project/linux/tools/perf", raw_path=0x0) at util/probe-event.c:518 #1 __show_line_range (module=<optimized out>, lr=0x839fd8 <params+9240>) at util/probe-event.c:641 #2 show_line_range (lr=lr@entry=0x839fd8 <params+9240>, module=<optimized out>) at util/probe-event.c:699 #3 0x000000000044667b in __cmd_probe (argc=<optimized out>, argv=argv@entry=0x7fff7a770ba0, prefix=<optimized out>) at builtin-probe.c:465 #4 0x00000000004469f4 in cmd_probe (argc=<optimized out>, argv=0x7fff7a770ba0, prefix=<optimized out>) at builtin-probe.c:520 #5 0x00000000004241b5 in run_builtin (p=p@entry=0x7ebde0 <commands+384>, argc=argc@entry=6, argv=argv@entry=0x7fff7a770ba0) at perf.c:319 #6 0x0000000000423a29 in handle_internal_command (argv=0x7fff7a770ba0, argc=6) at perf.c:376 #7 run_argv (argv=0x7fff7a7709a0, argcp=0x7fff7a7709ac) at perf.c:420 #8 main (argc=6, argv=0x7fff7a770ba0) at perf.c:529
Thanks, Namhyung
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