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Message-ID: <50399556C9727B4D88A595C8584AAB37526249BE@GSjpTKYDCembx32.service.hitachi.net> Date: Thu, 19 Nov 2015 02:56:57 +0000 From: 平松雅巳 / HIRAMATU，MASAMI <masami.hiramatsu.pt@...achi.com> To: "'Arnaldo Carvalho de Melo'" <acme@...nel.org> CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Adrian Hunter <adrian.hunter@...el.com>, "Ingo Molnar" <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>, Jiri Olsa <jolsa@...hat.com> Subject: RE: [PATCH perf/core 00/13] perf memory/refcnt leak fixes From: Arnaldo Carvalho de Melo [mailto:acme@...nel.org] > >Em Wed, Nov 18, 2015 at 03:40:09PM +0900, Masami Hiramatsu escreveu: >> Hi, >> >> Here is a series to fix some memory leaks and refcount >> leaks on map and dso. This also includes the refcnt APIs >> with backtrace debugging feature. > >Cool, I wonder if this could be usable in the kernel proper... Is there >such a facility there? I'll check. As far as I know, there is no same feature, but I guess expanding kmemleak is possible to provide similar feature. >But thanks for doing this work, I'll go thru the fixes first, then look >at the debugging feature. Thanks! > >- Arnaldo > >> The story has started from the posible memory leak report >> reported by Wnag Nan. >> I've tried to use valgrind to ensure the perf probe doesn't >> have other memory leaks. The result is here: >> >> ---- >> # valgrind ./perf probe vfs_read >> ==17521== Memcheck, a memory error detector >> ==17521== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al. >> ==17521== Using Valgrind-3.10.0 and LibVEX; rerun with -h for copyright info >> ==17521== Command: ./perf probe vfs_read >> ==17521== >> Added new event: >> probe:vfs_read (on vfs_read) >> >> You can now use it in all perf tools, such as: >> >> perf record -e probe:vfs_read -aR sleep 1 >> >> ==17521== >> ==17521== HEAP SUMMARY: >> ==17521== in use at exit: 3,512,761 bytes in 38,012 blocks >> ==17521== total heap usage: 74,723 allocs, 36,711 frees, 24,014,927 >> bytes allocated >> ==17521== >> ==17521== LEAK SUMMARY: >> ==17521== definitely lost: 6,857 bytes in 49 blocks >> ==17521== indirectly lost: 3,501,287 bytes in 37,891 blocks >> ==17521== possibly lost: 0 bytes in 0 blocks >> ==17521== still reachable: 4,617 bytes in 72 blocks >> ==17521== suppressed: 0 bytes in 0 blocks >> ==17521== Rerun with --leak-check=full to see details of leaked memory >> ==17521== >> ==17521== For counts of detected and suppressed errors, rerun with: -v >> ==17521== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2) >> ---- >> >> Oops! It leaked almost 4 MB memories. I've tried to find >> the root causes, and what I've found is there are many >> leaks in not only perf-probe specific code, but also maps >> and dsos (and some other pieces). >> >> The first 3 patches are just fixing 'easy' memory leaks. However, >> most of the leaks are caused by refcnt. Since valgrind seems not >> able to debug this kind of issues, I introduced a hand-made refcnt >> backtrace APIs for debugging. >> The rest of patches are for fixing refcnt leak bugs and replcing >> refcnt apis. >> >> After all, most of the issues are gone, except for just a few issues >> in elfutils. I'll continue to investigate that. >> >> ---- >> valgrind ./perf probe vfs_read >> ==29521== Memcheck, a memory error detector >> ==29521== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al. >> ==29521== Using Valgrind-3.10.0 and LibVEX; rerun with -h for copyright info >> ==29521== Command: ./perf probe vfs_read >> ==29521== >> Added new event: >> probe:vfs_read (on vfs_read) >> >> You can now use it in all perf tools, such as: >> >> perf record -e probe:vfs_read -aR sleep 1 >> >> ==29521== >> ==29521== HEAP SUMMARY: >> ==29521== in use at exit: 5,137 bytes in 75 blocks >> ==29521== total heap usage: 74,723 allocs, 74,648 frees, 24,014,927 >> bytes allocated >> ==29521== >> ==29521== LEAK SUMMARY: >> ==29521== definitely lost: 520 bytes in 3 blocks >> ==29521== indirectly lost: 0 bytes in 0 blocks >> ==29521== possibly lost: 0 bytes in 0 blocks >> ==29521== still reachable: 4,617 bytes in 72 blocks >> ==29521== suppressed: 0 bytes in 0 blocks >> ==29521== Rerun with --leak-check=full to see details of leaked memory >> ==29521== >> ==29521== For counts of detected and suppressed errors, rerun with: -v >> ==29521== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2) >> ---- >> >> Anyway, I decided to release these fixes and the debugging feature >> because at least this will improve perf quality. >> >> Thank you, >> >> --- >> >> Masami Hiramatsu (13): >> perf probe: Fix to free temporal Dwarf_Frame >> perf: Make perf_exec_path always returns malloc'd string >> perf: Introduce generic refcount APIs with debug feature >> perf: make map to use refcnt >> perf: Fix machine__findnew_module_map to put registered map >> perf: Fix machine__destroy_kernel_maps to put vmlinux_maps >> perf: Fix to destroy kernel maps when machine exits >> perf: Fix to put new map after inserting to map_groups in dso__load_sym >> perf: Make dso to use refcnt for debug >> perf: Fix __dsos__addnew to put dso after adding it to the list >> perf: Fix machine__create_kernel_maps to put kernel dso >> perf: Fix machine__findnew_module_map to put dso >> perf: Fix dso__load_sym to put dso >> >> >> tools/perf/config/Makefile | 5 ++ >> tools/perf/util/Build | 1 >> tools/perf/util/dso.c | 9 ++- >> tools/perf/util/exec_cmd.c | 20 ++++-- >> tools/perf/util/exec_cmd.h | 5 +- >> tools/perf/util/help.c | 6 +- >> tools/perf/util/machine.c | 17 ++++- >> tools/perf/util/map.c | 7 +- >> tools/perf/util/map.h | 3 + >> tools/perf/util/probe-finder.c | 9 ++- >> tools/perf/util/refcnt.c | 125 ++++++++++++++++++++++++++++++++++++++++ >> tools/perf/util/refcnt.h | 65 +++++++++++++++++++++ >> tools/perf/util/symbol-elf.c | 4 + >> 13 files changed, 250 insertions(+), 26 deletions(-) >> create mode 100644 tools/perf/util/refcnt.c >> create mode 100644 tools/perf/util/refcnt.h >> >> >> -- >> Masami HIRAMATSU >> Linux Technology Research Center, System Productivity Research Dept. >> Center for Technology Innovation - Systems Engineering >> Hitachi, Ltd., Research & Development Group >> E-mail: masami.hiramatsu.pt@...achi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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