linux-kernel - [PATCH 2/7] perf script: Fix crash with printing mixed trace point and other events

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190121183507.23490-3-acme@kernel.org>
Date:   Mon, 21 Jan 2019 15:35:02 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     Clark Williams <williams@...hat.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Jiri Olsa <jolsa@...nel.org>
Subject: [PATCH 2/7] perf script: Fix crash with printing mixed trace point and other events

From: Andi Kleen <ak@...ux.intel.com>

'perf script' crashes currently when printing mixed trace points and
other events because the trace format does not handle events without
trace meta data. Add a simple check to avoid that.

  % cat > test.c
  main()
  {
      printf("Hello world\n");
  }
  ^D
  % gcc -g -o test test.c
  % sudo perf probe -x test 'test.c:3'
  % perf record -e '{cpu/cpu-cycles,period=10000/,probe_test:main}:S' ./test
  % perf script
  <segfault>

Committer testing:

Before:

  # perf probe -x /lib64/libc-2.28.so malloc
  Added new event:
    probe_libc:malloc    (on malloc in /usr/lib64/libc-2.28.so)

  You can now use it in all perf tools, such as:

	perf record -e probe_libc:malloc -aR sleep 1

  # perf probe -l
  probe_libc:malloc    (on __libc_malloc@...loc/malloc.c in /usr/lib64/libc-2.28.so)
  # perf record -e '{cpu/cpu-cycles,period=10000/,probe_libc:*}:S' sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.023 MB perf.data (40 samples) ]
  # perf script
  Segmentation fault (core dumped)
  ^C
  #

After:

  # perf script | head -6
     sleep 2888 94796.944981: 16198 cpu/cpu-cycles,period=10000/: ffffffff925dc04f get_random_u32+0x1f (/lib/modules/5.0.0-rc2+/build/vmlinux)
     sleep 2888 [-01] 94796.944981: probe_libc:malloc:
     sleep 2888 94796.944983:  4713 cpu/cpu-cycles,period=10000/: ffffffff922763af change_protection+0xcf (/lib/modules/5.0.0-rc2+/build/vmlinux)
     sleep 2888 [-01] 94796.944983: probe_libc:malloc:
     sleep 2888 94796.944986:  9934 cpu/cpu-cycles,period=10000/: ffffffff922777e0 move_page_tables+0x0 (/lib/modules/5.0.0-rc2+/build/vmlinux)
     sleep 2888 [-01] 94796.944986: probe_libc:malloc:
  #

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Link: http://lkml.kernel.org/r/20190117194834.21940-1-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-script.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index d079f36d342d..357906ed1898 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1794,7 +1794,7 @@ static void process_event(struct perf_script *script,
 		return;
 	}
 
-	if (PRINT_FIELD(TRACE)) {
+	if (PRINT_FIELD(TRACE) && sample->raw_data) {
 		event_format__fprintf(evsel->tp_format, sample->cpu,
 				      sample->raw_data, sample->raw_size, fp);
 	}
-- 
2.20.1