Messages in this thread | | | Date | Tue, 01 Apr 2014 16:40:13 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: [PATCH] perf probe: Fix --line option behavior |
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(2014/04/01 16:21), Namhyung Kim wrote: > 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.
OK, thanks for this nice report! Hmm, line_range_inline_cb() must check the result of find_line_range_by_line() but ignored. That should be fixed too...
Thank you,
> > > (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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
-- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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