Re: [PATCH] perf symbol-elf: fix memory leak: free sdt_note.args

[Riccardo Mancini <rickyman7@gmail.com>]

Hi,

On Fri, 2021-06-04 at 10:00 -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Jun 03, 2021 at 09:08:46PM -0700, Ian Rogers escreveu:
> > On Wed, Jun 2, 2021 at 3:12 PM Riccardo Mancini <rickyman7@gmail.com> wrote:
> > > 
> > > Reported by ASan.
> > 
> > Did you have a reproducer for getting this to fail?

In case you'd like to add it to the commit message.

$ sudo ./perf record -- sleep 5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.025 MB perf.data (15 samples) ]

=================================================================
==79402==ERROR: LeakSanitizer: detected memory leaks

[...]

Direct leak of 999 byte(s) in 47 object(s) allocated from:
    #0 0x4b7cc7 in strdup (/home/user/linux/source/tools/perf/perf+0x4b7cc7)
    #1 0xac69db in populate_sdt_note /home/user/linux/source/tools/perf/util/symbol-elf.c:2256:15
    #2 0xac2b57 in construct_sdt_notes_list /home/user/linux/source/tools/perf/util/symbol-elf.c:2359:10
    #3 0xac2502 in get_sdt_note_list /home/user/linux/source/tools/perf/util/symbol-elf.c:2394:8
    #4 0xacc6ac in probe_cache__scan_sdt /home/user/linux/source/tools/perf/util/probe-file.c:882:8
    #5 0x7e2949 in build_id_cache__add_sdt_cache /home/user/linux/source/tools/perf/util/build-id.c:619:8
    #6 0x7e233c in build_id_cache__add /home/user/linux/source/tools/perf/util/build-id.c:779:6
    #7 0x7e2b37 in build_id_cache__add_s /home/user/linux/source/tools/perf/util/build-id.c:805:8
    #8 0x7e3e99 in build_id_cache__add_b /home/user/linux/source/tools/perf/util/build-id.c:821:9
    #9 0x7e3166 in dso__cache_build_id /home/user/linux/source/tools/perf/util/build-id.c:889:9
    #10 0x8da7bc in machine__for_each_dso /home/user/linux/source/tools/perf/util/machine.c:3167:7
    #11 0x7e2ec1 in machines__for_each_dso /home/user/linux/source/tools/perf/util/build-id.c:896:12
    #12 0x7e2e46 in __perf_session__cache_build_ids /home/user/linux/source/tools/perf/util/build-id.c:917:9
    #13 0x7e2faa in perf_session__cache_build_ids /home/user/linux/source/tools/perf/util/build-id.c:922:9
    #14 0x8996c8 in write_build_id /home/user/linux/source/tools/perf/util/header.c:327:2
    #15 0x8b76e9 in do_write_feat /home/user/linux/source/tools/perf/util/header.c:3216:9
    #16 0x8ac70d in perf_header__adds_write /home/user/linux/source/tools/perf/util/header.c:3261:7
    #17 0x8abe52 in perf_session__write_header /home/user/linux/source/tools/perf/util/header.c:3353:9
    #18 0x5961ed in record__finish_output /home/user/linux/source/tools/perf/builtin-record.c:1241:2
    #19 0x58e6ca in __cmd_record /home/user/linux/source/tools/perf/builtin-record.c:2060:4
    #20 0x58990b in cmd_record /home/user/linux/source/tools/perf/builtin-record.c:2901:8
    #21 0x7b2a20 in run_builtin /home/user/linux/source/tools/perf/perf.c:313:11
    #22 0x7b12ff in handle_internal_command /home/user/linux/source/tools/perf/perf.c:365:8
    #23 0x7b2583 in run_argv /home/user/linux/source/tools/perf/perf.c:409:2
    #24 0x7b0d79 in main /home/user/linux/source/tools/perf/perf.c:539:3
    #25 0x7effc1a65b74 in __libc_start_main /usr/src/debug/glibc-2.33-8.fc34.x86_64/csu/../csu/libc-start.c:332:16

Thanks,
Riccardo

> > 
> > > Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
> > 
> > Acked-by: Ian Rogers <irogers@google.com>
> 
> Thanks, applied.
> 
> - Arnaldo
> 
>  
> > Thanks,
> > Ian
> > 
> > > ---
> > >  tools/perf/util/symbol-elf.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> > > index 4c56aa8374344..a73345730ba90 100644
> > > --- a/tools/perf/util/symbol-elf.c
> > > +++ b/tools/perf/util/symbol-elf.c
> > > @@ -2412,6 +2412,7 @@ int cleanup_sdt_note_list(struct list_head *sdt_notes)
> > > 
> > >         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
> > >                 list_del_init(&pos->note_list);
> > > +               zfree(&pos->args);
> > >                 zfree(&pos->name);
> > >                 zfree(&pos->provider);
> > >                 free(pos);
> > > --
> > > 2.31.1
> > > 
>