lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 12 Oct 2017 22:00:52 +0800 From: Wang Nan <wangnan0@...wei.com> To: <linux-kernel@...r.kernel.org>, <kan.liang@...el.com>, <acme@...nel.org> CC: Wang Nan <wangnan0@...wei.com>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>, Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Adrian Hunter <adrian.hunter@...el.com>, Andi Kleen <ak@...ux.intel.com>, Li Zefan <lizefan@...wei.com> Subject: [PATCH] perf tools: fix: Force backward ring buffer mapped readonly perf record's --overwrite option doesn't work as we expect. For example: $ ~/linux/tools/perf$ sudo rm ./perf.data* rm: cannot remove './perf.data*': No such file or directory : ~/linux/tools/perf$ sudo ./perf record -m 4 -e raw_syscalls:* -g --overwrite \ --switch-output=1s --tail-synthesize dd if=/dev/zero of=/dev/null [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221460002 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221460102 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221460202 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221460302 ] ^C[ perf record: Woken up 1 times to write data ] 2066346+0 records in 2066346+0 records out 1057969152 bytes (1.1 GB, 1009 MiB) copied, 4.25983 s, 248 MB/s [ perf record: Dump perf.data.2017101221460332 ] [ perf record: Captured and wrote 0.034 MB perf.data.<timestamp> ] $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221460002 | head -n 1 dd 3918 [006] 182589.668954: raw_syscalls:sys_exit: NR 59 = 0 $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221460102 | head -n 1 dd 3918 [006] 182589.668954: raw_syscalls:sys_exit: NR 59 = 0 $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221460202 | head -n 1 dd 3918 [006] 182589.668954: raw_syscalls:sys_exit: NR 59 = 0 $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221460302 | head -n 1 dd 3918 [006] 182589.668954: raw_syscalls:sys_exit: NR 59 = 0 In the above example we get same records from the backward ring buffer all the time. Overwriting is not triggered. This commit maps backward ring buffers readonly, make it overwritable. It is safe because we assume backward ring buffer always overwritable in other part of code. After applying this patch: $ ~/linux/tools/perf$ sudo ./perf record -m 4 -e raw_syscalls:* -g --overwrite \ --switch-output=1s --tail-synthesize dd if=/dev/zero of=/dev/null [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221540350 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221540451 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221540551 ] [ perf record: dump data: Woken up 1 times ] [ perf record: Dump perf.data.2017101221540651 ] ^C[ perf record: Woken up 1 times to write data ] 1604606+0 records in 1604605+0 records out 821557760 bytes (822 MB, 783 MiB) copied, 4.42736 s, 186 MB/s [ perf record: Dump perf.data.2017101221540700 ] [ perf record: Captured and wrote 0.034 MB perf.data.<timestamp> ] $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221540350 | head -n 1 dd 5126 [003] 183074.104581: raw_syscalls:sys_exit: NR 0 = 512 $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221540451 | head -n 1 dd 5126 [003] 183075.106496: raw_syscalls:sys_exit: NR 1 = 512 $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221540551 | head -n 1 dd 5126 [003] 183076.108093: raw_syscalls:sys_enter: NR 1 (1, af8000, 200, 871, 0, af8060) $ ~/linux/tools/perf$ sudo ./perf script -i ./perf.data.2017101221540651 | head -n 1 dd 5126 [003] 183077.109676: raw_syscalls:sys_exit: NR 1 = 512 Signed-off-by: Wang Nan <wangnan0@...wei.com> Cc: Liang Kan <kan.liang@...el.com> Cc: Arnaldo Carvalho de Melo <acme@...nel.org> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Ingo Molnar <mingo@...nel.org> Cc: Jiri Olsa <jolsa@...nel.org> Cc: Namhyung Kim <namhyung@...nel.org> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com> Cc: Adrian Hunter <adrian.hunter@...el.com> Cc: Andi Kleen <ak@...ux.intel.com> Cc: Li Zefan <lizefan@...wei.com> --- tools/perf/util/evlist.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index c6c891e..a86b0d2 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -799,12 +799,14 @@ perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused, } static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, - struct mmap_params *mp, int cpu_idx, + struct mmap_params *_mp, int cpu_idx, int thread, int *_output, int *_output_backward) { struct perf_evsel *evsel; int revent; int evlist_cpu = cpu_map__cpu(evlist->cpus, cpu_idx); + struct mmap_params *mp = _mp; + struct mmap_params backward_mp; evlist__for_each_entry(evlist, evsel) { struct perf_mmap *maps = evlist->mmap; @@ -815,6 +817,9 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, if (evsel->attr.write_backward) { output = _output_backward; maps = evlist->backward_mmap; + backward_mp = *mp; + backward_mp.prot &= ~PROT_WRITE; + mp = &backward_mp; if (!maps) { maps = perf_evlist__alloc_mmap(evlist); -- 2.9.3
Powered by blists - more mailing lists