Re: [PATCH v2 2/2] perf report: Fix memory leaks in the hierarchy mode

[Ian Rogers]

On Fri, Mar 7, 2025 at 8:28 AM Falcon, Thomas <thomas.falcon@xxxxxxxxx> wrote:
>
> On Thu, 2025-03-06 at 22:12 -0800, Namhyung Kim wrote:
> > Ian told me that there are many memory leaks in the hierarchy mode.
> > I
> > can easily reproduce it with the follwing command.
> >
> >   $ make DEBUG=1 EXTRA_CFLAGS=-fsanitize=leak
> >
> >   $ perf record --latency -g -- ./perf test -w thloop
> >
> >   $ perf report -H --stdio
> >   ...
> >   Indirect leak of 168 byte(s) in 21 object(s) allocated from:
> >       #0 0x7f3414c16c65 in malloc
> > ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:75
> >       #1 0x55ed3602346e in map__get util/map.h:189
> >       #2 0x55ed36024cc4 in hist_entry__init util/hist.c:476
> >       #3 0x55ed36025208 in hist_entry__new util/hist.c:588
> >       #4 0x55ed36027c05 in hierarchy_insert_entry util/hist.c:1587
> >       #5 0x55ed36027e2e in hists__hierarchy_insert_entry
> > util/hist.c:1638
> >       #6 0x55ed36027fa4 in hists__collapse_insert_entry
> > util/hist.c:1685
> >       #7 0x55ed360283e8 in hists__collapse_resort util/hist.c:1776
> >       #8 0x55ed35de0323 in report__collapse_hists
> > /home/namhyung/project/linux/tools/perf/builtin-report.c:735
> >       #9 0x55ed35de15b4 in __cmd_report
> > /home/namhyung/project/linux/tools/perf/builtin-report.c:1119
> >       #10 0x55ed35de43dc in cmd_report
> > /home/namhyung/project/linux/tools/perf/builtin-report.c:1867
> >       #11 0x55ed35e66767 in run_builtin
> > /home/namhyung/project/linux/tools/perf/perf.c:351
> >       #12 0x55ed35e66a0e in handle_internal_command
> > /home/namhyung/project/linux/tools/perf/perf.c:404
> >       #13 0x55ed35e66b67 in run_argv
> > /home/namhyung/project/linux/tools/perf/perf.c:448
> >       #14 0x55ed35e66eb0 in main
> > /home/namhyung/project/linux/tools/perf/perf.c:556
> >       #15 0x7f340ac33d67 in __libc_start_call_main
> > ../sysdeps/nptl/libc_start_call_main.h:58
> >   ...
> >
> >   $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak'
> >   93
> >
> > I found that hist_entry__delete() missed to release child entries in
> > the
> > hierarchy tree (hroot_{in,out}).  It needs to iterate the child
> > entries
> > and call hist_entry__delete() recursively.
> >
> > After this change:
> >
> >   $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak'
> >   0
> >
> > Reported-by: Ian Rogers <irogers@xxxxxxxxxx>
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
>
> Tested on an Arrow Lake system.
>
> Tested-by Thomas Falcon <thomas.falcon@xxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks!
Ian