<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools/perf/tests, branch v5.4.78</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>perf test session topology: Fix data path</title>
<updated>2020-10-14T08:32:59+00:00</updated>
<author>
<name>Tommi Rantala</name>
<email>tommi.t.rantala@nokia.com</email>
</author>
<published>2020-04-23T11:53:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2499c15115ac2e426df5f1075f3968293d1d5f3f'/>
<id>2499c15115ac2e426df5f1075f3968293d1d5f3f</id>
<content type='text'>
commit dbd660e6b2884b864d2642d930a163d3bcebe4be upstream.

Commit 2d4f27999b88 ("perf data: Add global path holder") missed path
conversion in tests/topology.c, causing the "Session topology" testcase
to "hang" (waits forever for input from stdin) when doing "ssh $VM perf
test".

Can be reproduced by running "cat | perf test topo", and crashed by
replacing cat with true:

  $ true | perf test -v topo
  40: Session topology                                      :
  --- start ---
  test child forked, pid 3638
  templ file: /tmp/perf-test-QPvAch
  incompatible file format
  incompatible file format (rerun with -v to learn more)
  free(): invalid pointer
  test child interrupted
  ---- end ----
  Session topology: FAILED!

Committer testing:

Reproduced the above result before the patch and after it is back
working:

  # true | perf test -v topo
  41: Session topology                                      :
  --- start ---
  test child forked, pid 19374
  templ file: /tmp/perf-test-YOTEQg
  CPU 0, core 0, socket 0
  CPU 1, core 1, socket 0
  CPU 2, core 2, socket 0
  CPU 3, core 3, socket 0
  CPU 4, core 0, socket 0
  CPU 5, core 1, socket 0
  CPU 6, core 2, socket 0
  CPU 7, core 3, socket 0
  test child finished with 0
  ---- end ----
  Session topology: Ok
  #

Fixes: 2d4f27999b88 ("perf data: Add global path holder")
Signed-off-by: Tommi Rantala &lt;tommi.t.rantala@nokia.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mamatha Inamdar &lt;mamatha4@linux.vnet.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200423115341.562782-1-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit dbd660e6b2884b864d2642d930a163d3bcebe4be upstream.

Commit 2d4f27999b88 ("perf data: Add global path holder") missed path
conversion in tests/topology.c, causing the "Session topology" testcase
to "hang" (waits forever for input from stdin) when doing "ssh $VM perf
test".

Can be reproduced by running "cat | perf test topo", and crashed by
replacing cat with true:

  $ true | perf test -v topo
  40: Session topology                                      :
  --- start ---
  test child forked, pid 3638
  templ file: /tmp/perf-test-QPvAch
  incompatible file format
  incompatible file format (rerun with -v to learn more)
  free(): invalid pointer
  test child interrupted
  ---- end ----
  Session topology: FAILED!

Committer testing:

Reproduced the above result before the patch and after it is back
working:

  # true | perf test -v topo
  41: Session topology                                      :
  --- start ---
  test child forked, pid 19374
  templ file: /tmp/perf-test-YOTEQg
  CPU 0, core 0, socket 0
  CPU 1, core 1, socket 0
  CPU 2, core 2, socket 0
  CPU 3, core 3, socket 0
  CPU 4, core 0, socket 0
  CPU 5, core 1, socket 0
  CPU 6, core 2, socket 0
  CPU 7, core 3, socket 0
  test child finished with 0
  ---- end ----
  Session topology: Ok
  #

Fixes: 2d4f27999b88 ("perf data: Add global path holder")
Signed-off-by: Tommi Rantala &lt;tommi.t.rantala@nokia.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mamatha Inamdar &lt;mamatha4@linux.vnet.ibm.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200423115341.562782-1-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>perf tests: Fix test 68 zstd compression for s390</title>
<updated>2020-10-01T11:18:11+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2020-07-29T13:53:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e1ad5cf63e402c37a4e18d84921bc5d4e37230e4'/>
<id>e1ad5cf63e402c37a4e18d84921bc5d4e37230e4</id>
<content type='text'>
[ Upstream commit 463538a383a27337cb83ae195e432a839a52d639 ]

Commit 5aa98879efe7 ("s390/cpum_sf: prohibit callchain data collection")
prohibits call graph sampling for hardware events on s390. The
information recorded is out of context and does not match.

On s390 this commit now breaks test case 68 Zstd perf.data
compression/decompression.

Therefore omit call graph sampling on s390 in this test.

Output before:
  [root@t35lp46 perf]# ./perf test -Fv 68
  68: Zstd perf.data compression/decompression              :
  --- start ---
  Collecting compressed record file:
  Error:
  cycles: PMU Hardware doesn't support sampling/overflow-interrupts.
                                Try 'perf stat'
  ---- end ----
  Zstd perf.data compression/decompression: FAILED!
  [root@t35lp46 perf]#

Output after:
[root@t35lp46 perf]# ./perf test -Fv 68
  68: Zstd perf.data compression/decompression              :
  --- start ---
  Collecting compressed record file:
  500+0 records in
  500+0 records out
  256000 bytes (256 kB, 250 KiB) copied, 0.00615638 s, 41.6 MB/s
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.004 MB /tmp/perf.data.X3M,
                        compressed (original 0.002 MB, ratio is 3.609) ]
  Checking compressed events stats:
  # compressed : Zstd, level = 1, ratio = 4
        COMPRESSED events:          1
  2ELIFREPh---- end ----
  Zstd perf.data compression/decompression: Ok
  [root@t35lp46 perf]#

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Reviewed-by: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200729135314.91281-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 463538a383a27337cb83ae195e432a839a52d639 ]

Commit 5aa98879efe7 ("s390/cpum_sf: prohibit callchain data collection")
prohibits call graph sampling for hardware events on s390. The
information recorded is out of context and does not match.

On s390 this commit now breaks test case 68 Zstd perf.data
compression/decompression.

Therefore omit call graph sampling on s390 in this test.

Output before:
  [root@t35lp46 perf]# ./perf test -Fv 68
  68: Zstd perf.data compression/decompression              :
  --- start ---
  Collecting compressed record file:
  Error:
  cycles: PMU Hardware doesn't support sampling/overflow-interrupts.
                                Try 'perf stat'
  ---- end ----
  Zstd perf.data compression/decompression: FAILED!
  [root@t35lp46 perf]#

Output after:
[root@t35lp46 perf]# ./perf test -Fv 68
  68: Zstd perf.data compression/decompression              :
  --- start ---
  Collecting compressed record file:
  500+0 records in
  500+0 records out
  256000 bytes (256 kB, 250 KiB) copied, 0.00615638 s, 41.6 MB/s
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.004 MB /tmp/perf.data.X3M,
                        compressed (original 0.002 MB, ratio is 3.609) ]
  Checking compressed events stats:
  # compressed : Zstd, level = 1, ratio = 4
        COMPRESSED events:          1
  2ELIFREPh---- end ----
  Zstd perf.data compression/decompression: Ok
  [root@t35lp46 perf]#

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Reviewed-by: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200729135314.91281-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Fix test trace+probe_vfs_getname.sh on s390</title>
<updated>2020-10-01T11:17:34+00:00</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2020-02-17T10:21:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=45901923749f4fc3a34e6d7fbdc7e779662e2569'/>
<id>45901923749f4fc3a34e6d7fbdc7e779662e2569</id>
<content type='text'>
[ Upstream commit 2bbc83537614517730e9f2811195004b712de207 ]

This test places a kprobe to function getname_flags() in the kernel
which has the following prototype:

  struct filename *getname_flags(const char __user *filename, int flags, int *empty)

The 'filename' argument points to a filename located in user space memory.

Looking at commit 88903c464321c ("tracing/probe: Add ustring type for
user-space string") the kprobe should indicate that user space memory is
accessed.

Output before:

   [root@m35lp76 perf]# ./perf test 66 67
   66: Use vfs_getname probe to get syscall args filenames   : FAILED!
   67: Check open filename arg using perf trace + vfs_getname: FAILED!
   [root@m35lp76 perf]#

Output after:

   [root@m35lp76 perf]# ./perf test 66 67
   66: Use vfs_getname probe to get syscall args filenames   : Ok
   67: Check open filename arg using perf trace + vfs_getname: Ok
   [root@m35lp76 perf]#

Comments from Masami Hiramatsu:

This bug doesn't happen on x86 or other archs on which user address
space and kernel address space is the same. On some arches (ppc64 in
this case?) user address space is partially or completely the same as
kernel address space.

(Yes, they switch the world when running into the kernel) In this case,
we need to use different data access functions for each space.

That is why I introduced the "ustring" type for kprobe events.

As far as I can see, Thomas's patch is sane. Thomas, could you show us
your result on your test environment?

Comments from Thomas Richter:

Test results for s/390 included above.

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200217102111.61137-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2bbc83537614517730e9f2811195004b712de207 ]

This test places a kprobe to function getname_flags() in the kernel
which has the following prototype:

  struct filename *getname_flags(const char __user *filename, int flags, int *empty)

The 'filename' argument points to a filename located in user space memory.

Looking at commit 88903c464321c ("tracing/probe: Add ustring type for
user-space string") the kprobe should indicate that user space memory is
accessed.

Output before:

   [root@m35lp76 perf]# ./perf test 66 67
   66: Use vfs_getname probe to get syscall args filenames   : FAILED!
   67: Check open filename arg using perf trace + vfs_getname: FAILED!
   [root@m35lp76 perf]#

Output after:

   [root@m35lp76 perf]# ./perf test 66 67
   66: Use vfs_getname probe to get syscall args filenames   : Ok
   67: Check open filename arg using perf trace + vfs_getname: Ok
   [root@m35lp76 perf]#

Comments from Masami Hiramatsu:

This bug doesn't happen on x86 or other archs on which user address
space and kernel address space is the same. On some arches (ppc64 in
this case?) user address space is partially or completely the same as
kernel address space.

(Yes, they switch the world when running into the kernel) In this case,
we need to use different data access functions for each space.

That is why I introduced the "ustring" type for kprobe events.

As far as I can see, Thomas's patch is sane. Thomas, could you show us
your result on your test environment?

Comments from Thomas Richter:

Test results for s/390 included above.

Signed-off-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/lkml/20200217102111.61137-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Free formats for perf pmu parse test</title>
<updated>2020-09-23T10:40:41+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2020-09-15T03:18:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b7b136191170e08b12f356445d587fc90e34806b'/>
<id>b7b136191170e08b12f356445d587fc90e34806b</id>
<content type='text'>
[ Upstream commit d26383dcb2b4b8629fde05270b4e3633be9e3d4b ]

The following leaks were detected by ASAN:

  Indirect leak of 360 byte(s) in 9 object(s) allocated from:
    #0 0x7fecc305180e in calloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10780e)
    #1 0x560578f6dce5 in perf_pmu__new_format util/pmu.c:1333
    #2 0x560578f752fc in perf_pmu_parse util/pmu.y:59
    #3 0x560578f6a8b7 in perf_pmu__format_parse util/pmu.c:73
    #4 0x560578e07045 in test__pmu tests/pmu.c:155
    #5 0x560578de109b in run_test tests/builtin-test.c:410
    #6 0x560578de109b in test_and_print tests/builtin-test.c:440
    #7 0x560578de401a in __cmd_test tests/builtin-test.c:661
    #8 0x560578de401a in cmd_test tests/builtin-test.c:807
    #9 0x560578e49354 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
    #10 0x560578ce71a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
    #11 0x560578ce71a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
    #12 0x560578ce71a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
    #13 0x7fecc2b7acc9 in __libc_start_main ../csu/libc-start.c:308

Fixes: cff7f956ec4a1 ("perf tests: Move pmu tests into separate object")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: http://lore.kernel.org/lkml/20200915031819.386559-12-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d26383dcb2b4b8629fde05270b4e3633be9e3d4b ]

The following leaks were detected by ASAN:

  Indirect leak of 360 byte(s) in 9 object(s) allocated from:
    #0 0x7fecc305180e in calloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10780e)
    #1 0x560578f6dce5 in perf_pmu__new_format util/pmu.c:1333
    #2 0x560578f752fc in perf_pmu_parse util/pmu.y:59
    #3 0x560578f6a8b7 in perf_pmu__format_parse util/pmu.c:73
    #4 0x560578e07045 in test__pmu tests/pmu.c:155
    #5 0x560578de109b in run_test tests/builtin-test.c:410
    #6 0x560578de109b in test_and_print tests/builtin-test.c:440
    #7 0x560578de401a in __cmd_test tests/builtin-test.c:661
    #8 0x560578de401a in cmd_test tests/builtin-test.c:807
    #9 0x560578e49354 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
    #10 0x560578ce71a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
    #11 0x560578ce71a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
    #12 0x560578ce71a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
    #13 0x7fecc2b7acc9 in __libc_start_main ../csu/libc-start.c:308

Fixes: cff7f956ec4a1 ("perf tests: Move pmu tests into separate object")
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: http://lore.kernel.org/lkml/20200915031819.386559-12-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Fix the "signal" test inline assembly</title>
<updated>2020-09-23T10:40:40+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2020-09-11T13:00:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b86434c072d4d41d6ff570796fc28c3d058c1d8b'/>
<id>b86434c072d4d41d6ff570796fc28c3d058c1d8b</id>
<content type='text'>
[ Upstream commit 8a39e8c4d9baf65d88f66d49ac684df381e30055 ]

When compiling with DEBUG=1 on Fedora 32 I'm getting crash for 'perf
test signal':

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000c68548 in __test_function ()
  (gdb) bt
  #0  0x0000000000c68548 in __test_function ()
  #1  0x00000000004d62e9 in test_function () at tests/bp_signal.c:61
  #2  0x00000000004d689a in test__bp_signal (test=0xa8e280 &lt;generic_ ...
  #3  0x00000000004b7d49 in run_test (test=0xa8e280 &lt;generic_tests+1 ...
  #4  0x00000000004b7e7f in test_and_print (t=0xa8e280 &lt;generic_test ...
  #5  0x00000000004b8927 in __cmd_test (argc=1, argv=0x7fffffffdce0, ...
  ...

It's caused by the symbol __test_function being in the ".bss" section:

  $ readelf -a ./perf | less
    [Nr] Name              Type             Address           Offset
         Size              EntSize          Flags  Link  Info  Align
    ...
    [28] .bss              NOBITS           0000000000c356a0  008346a0
         00000000000511f8  0000000000000000  WA       0     0     32

  $ nm perf | grep __test_function
  0000000000c68548 B __test_function

I guess most of the time we're just lucky the inline asm ended up in the
".text" section, so making it specific explicit with push and pop
section clauses.

  $ readelf -a ./perf | less
    [Nr] Name              Type             Address           Offset
         Size              EntSize          Flags  Link  Info  Align
    ...
    [13] .text             PROGBITS         0000000000431240  00031240
         0000000000306faa  0000000000000000  AX       0     0     16

  $ nm perf | grep __test_function
  00000000004d62c8 T __test_function

Committer testing:

  $ readelf -wi ~/bin/perf | grep producer -m1
    &lt;c&gt;   DW_AT_producer    : (indirect string, offset: 0x254a): GNU C99 10.2.1 20200723 (Red Hat 10.2.1-1) -mtune=generic -march=x86-64 -ggdb3 -std=gnu99 -fno-omit-frame-pointer -funwind-tables -fstack-protector-all
                                                                                                                                         ^^^^^
                                                                                                                                         ^^^^^
                                                                                                                                         ^^^^^
  $

Before:

  $ perf test signal
  20: Breakpoint overflow signal handler                    : FAILED!
  $

After:

  $ perf test signal
  20: Breakpoint overflow signal handler                    : Ok
  $

Fixes: 8fd34e1cce18 ("perf test: Improve bp_signal")
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20200911130005.1842138-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8a39e8c4d9baf65d88f66d49ac684df381e30055 ]

When compiling with DEBUG=1 on Fedora 32 I'm getting crash for 'perf
test signal':

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000c68548 in __test_function ()
  (gdb) bt
  #0  0x0000000000c68548 in __test_function ()
  #1  0x00000000004d62e9 in test_function () at tests/bp_signal.c:61
  #2  0x00000000004d689a in test__bp_signal (test=0xa8e280 &lt;generic_ ...
  #3  0x00000000004b7d49 in run_test (test=0xa8e280 &lt;generic_tests+1 ...
  #4  0x00000000004b7e7f in test_and_print (t=0xa8e280 &lt;generic_test ...
  #5  0x00000000004b8927 in __cmd_test (argc=1, argv=0x7fffffffdce0, ...
  ...

It's caused by the symbol __test_function being in the ".bss" section:

  $ readelf -a ./perf | less
    [Nr] Name              Type             Address           Offset
         Size              EntSize          Flags  Link  Info  Align
    ...
    [28] .bss              NOBITS           0000000000c356a0  008346a0
         00000000000511f8  0000000000000000  WA       0     0     32

  $ nm perf | grep __test_function
  0000000000c68548 B __test_function

I guess most of the time we're just lucky the inline asm ended up in the
".text" section, so making it specific explicit with push and pop
section clauses.

  $ readelf -a ./perf | less
    [Nr] Name              Type             Address           Offset
         Size              EntSize          Flags  Link  Info  Align
    ...
    [13] .text             PROGBITS         0000000000431240  00031240
         0000000000306faa  0000000000000000  AX       0     0     16

  $ nm perf | grep __test_function
  00000000004d62c8 T __test_function

Committer testing:

  $ readelf -wi ~/bin/perf | grep producer -m1
    &lt;c&gt;   DW_AT_producer    : (indirect string, offset: 0x254a): GNU C99 10.2.1 20200723 (Red Hat 10.2.1-1) -mtune=generic -march=x86-64 -ggdb3 -std=gnu99 -fno-omit-frame-pointer -funwind-tables -fstack-protector-all
                                                                                                                                         ^^^^^
                                                                                                                                         ^^^^^
                                                                                                                                         ^^^^^
  $

Before:

  $ perf test signal
  20: Breakpoint overflow signal handler                    : FAILED!
  $

After:

  $ perf test signal
  20: Breakpoint overflow signal handler                    : Ok
  $

Fixes: 8fd34e1cce18 ("perf test: Improve bp_signal")
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20200911130005.1842138-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tests bp_account: Make global variable static</title>
<updated>2020-08-05T07:59:52+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2020-03-02T14:13:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=73d2d6b421dfdc66b4615452a94efcece27a3c21'/>
<id>73d2d6b421dfdc66b4615452a94efcece27a3c21</id>
<content type='text'>
commit cff20b3151ccab690715cb6cf0f5da5cccb32adf upstream.

To fix the build with newer gccs, that without this patch exit with:

    LD       /tmp/build/perf/tests/perf-in.o
  ld: /tmp/build/perf/tests/bp_account.o:/git/perf/tools/perf/tests/bp_account.c:22: multiple definition of `the_var'; /tmp/build/perf/tests/bp_signal.o:/git/perf/tools/perf/tests/bp_signal.c:38: first defined here
  make[4]: *** [/git/perf/tools/build/Makefile.build:145: /tmp/build/perf/tests/perf-in.o] Error 1

First noticed in fedora:rawhide/32 with:

  [perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
  gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)

Reported-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cff20b3151ccab690715cb6cf0f5da5cccb32adf upstream.

To fix the build with newer gccs, that without this patch exit with:

    LD       /tmp/build/perf/tests/perf-in.o
  ld: /tmp/build/perf/tests/bp_account.o:/git/perf/tools/perf/tests/bp_account.c:22: multiple definition of `the_var'; /tmp/build/perf/tests/bp_signal.o:/git/perf/tools/perf/tests/bp_signal.c:38: first defined here
  make[4]: *** [/git/perf/tools/build/Makefile.build:145: /tmp/build/perf/tests/perf-in.o] Error 1

First noticed in fedora:rawhide/32 with:

  [perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
  gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)

Reported-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>perf tests: Disable bp_signal testing for arm64</title>
<updated>2019-12-31T15:44:12+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2019-10-18T08:55:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dbb6e6f052d72c23aaf4771797e43ca5111f1edf'/>
<id>dbb6e6f052d72c23aaf4771797e43ca5111f1edf</id>
<content type='text'>
[ Upstream commit 6a5f3d94cb69a185b921cb92c39888dc31009acb ]

As there are several discussions for enabling perf breakpoint signal
testing on arm64 platform: arm64 needs to rely on single-step to execute
the breakpointed instruction and then reinstall the breakpoint exception
handler.  But if we hook the breakpoint with a signal, the signal
handler will do the stepping rather than the breakpointed instruction,
this causes infinite loops as below:

         Kernel space              |            Userspace
  ---------------------------------|--------------------------------
                                   |  __test_function() -&gt; hit
				   |                       breakpoint
  breakpoint_handler()             |
    `-&gt; user_enable_single_step()  |
  do_signal()                      |
                                   |  sig_handler() -&gt; Step one
				   |                instruction and
				   |                trap to kernel
  single_step_handler()            |
    `-&gt; reinstall_suspended_bps()  |
                                   |  __test_function() -&gt; hit
				   |     breakpoint again and
				   |     repeat up flow infinitely

As Will Deacon mentioned [1]: "that we require the overflow handler to
do the stepping on arm/arm64, which is relied upon by GDB/ptrace. The
hw_breakpoint code is a complete disaster so my preference would be to
rip out the perf part and just implement something directly in ptrace,
but it's a pretty horrible job".  Though Will commented this on arm
architecture, but the comment also can apply on arm64 architecture.

For complete information, I searched online and found a few years back,
Wang Nan sent one patch 'arm64: Store breakpoint single step state into
pstate' [2]; the patch tried to resolve this issue by avoiding single
stepping in signal handler and defer to enable the signal stepping when
return to __test_function().  The fixing was not merged due to the
concern for missing to handle different usage cases.

Based on the info, the most feasible way is to skip Perf breakpoint
signal testing for arm64 and this could avoid the duplicate
investigation efforts when people see the failure.  This patch skips
this case on arm64 platform, which is same with arm architecture.

[1] https://lkml.org/lkml/2018/11/15/205
[2] https://lkml.org/lkml/2015/12/23/477

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Brajeswar Ghosh &lt;brajeswar.linux@gmail.com&gt;
Cc: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Souptick Joarder &lt;jrdr.linux@gmail.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191018085531.6348-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6a5f3d94cb69a185b921cb92c39888dc31009acb ]

As there are several discussions for enabling perf breakpoint signal
testing on arm64 platform: arm64 needs to rely on single-step to execute
the breakpointed instruction and then reinstall the breakpoint exception
handler.  But if we hook the breakpoint with a signal, the signal
handler will do the stepping rather than the breakpointed instruction,
this causes infinite loops as below:

         Kernel space              |            Userspace
  ---------------------------------|--------------------------------
                                   |  __test_function() -&gt; hit
				   |                       breakpoint
  breakpoint_handler()             |
    `-&gt; user_enable_single_step()  |
  do_signal()                      |
                                   |  sig_handler() -&gt; Step one
				   |                instruction and
				   |                trap to kernel
  single_step_handler()            |
    `-&gt; reinstall_suspended_bps()  |
                                   |  __test_function() -&gt; hit
				   |     breakpoint again and
				   |     repeat up flow infinitely

As Will Deacon mentioned [1]: "that we require the overflow handler to
do the stepping on arm/arm64, which is relied upon by GDB/ptrace. The
hw_breakpoint code is a complete disaster so my preference would be to
rip out the perf part and just implement something directly in ptrace,
but it's a pretty horrible job".  Though Will commented this on arm
architecture, but the comment also can apply on arm64 architecture.

For complete information, I searched online and found a few years back,
Wang Nan sent one patch 'arm64: Store breakpoint single step state into
pstate' [2]; the patch tried to resolve this issue by avoiding single
stepping in signal handler and defer to enable the signal stepping when
return to __test_function().  The fixing was not merged due to the
concern for missing to handle different usage cases.

Based on the info, the most feasible way is to skip Perf breakpoint
signal testing for arm64 and this could avoid the duplicate
investigation efforts when people see the failure.  This patch skips
this case on arm64 platform, which is same with arm architecture.

[1] https://lkml.org/lkml/2018/11/15/205
[2] https://lkml.org/lkml/2015/12/23/477

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Brajeswar Ghosh &lt;brajeswar.linux@gmail.com&gt;
Cc: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Souptick Joarder &lt;jrdr.linux@gmail.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191018085531.6348-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Avoid infinite loop for task exit case</title>
<updated>2019-12-31T15:44:06+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2019-10-11T09:19:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5bd1406c516c8be8f53e9cd0774d3321ab3f5242'/>
<id>5bd1406c516c8be8f53e9cd0774d3321ab3f5242</id>
<content type='text'>
[ Upstream commit 791ce9c48c79210d2ffcdbe69421e7783b32921f ]

When executing the task exit testing case, perf gets stuck in an endless
loop this case and doesn't return back on Arm64 Juno board.

After digging into this issue, since Juno board has Arm's big.LITTLE
CPUs, thus the PMUs are not compatible between the big CPUs and little
CPUs.  This leads to a PMU event that cannot be enabled properly when
the traced task is migrated from one variant's CPU to another variant.
Finally, the test case runs into infinite loop for cannot read out any
event data after return from polling.

Eventually, we need to work out formal solution to allow PMU events can
be freely migrated from one CPU variant to another, but this is a
difficult task and a different topic.  This patch tries to fix the Perf
test case to avoid infinite loop, when the testing detects 1000 times
retrying for reading empty events, it will directly bail out and return
failure.  This allows the Perf tool can continue its other test cases.

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191011091942.29841-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 791ce9c48c79210d2ffcdbe69421e7783b32921f ]

When executing the task exit testing case, perf gets stuck in an endless
loop this case and doesn't return back on Arm64 Juno board.

After digging into this issue, since Juno board has Arm's big.LITTLE
CPUs, thus the PMUs are not compatible between the big CPUs and little
CPUs.  This leads to a PMU event that cannot be enabled properly when
the traced task is migrated from one variant's CPU to another variant.
Finally, the test case runs into infinite loop for cannot read out any
event data after return from polling.

Eventually, we need to work out formal solution to allow PMU events can
be freely migrated from one CPU variant to another, but this is a
difficult task and a different topic.  This patch tries to fix the Perf
test case to avoid infinite loop, when the testing detects 1000 times
retrying for reading empty events, it will directly bail out and return
failure.  This allows the Perf tool can continue its other test cases.

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191011091942.29841-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf test: Report failure for mmap events</title>
<updated>2019-12-31T15:44:06+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2019-10-11T09:19:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=56596e13ecd292b2a28dbf96f9052a088a1ce845'/>
<id>56596e13ecd292b2a28dbf96f9052a088a1ce845</id>
<content type='text'>
[ Upstream commit 6add129c5d9210ada25217abc130df0b7096ee02 ]

When fail to mmap events in task exit case, it misses to set 'err' to
-1; thus the testing will not report failure for it.

This patch sets 'err' to -1 when fails to mmap events, thus Perf tool
can report correct result.

Fixes: d723a55096b8 ("perf test: Add test case for checking number of EXIT events")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191011091942.29841-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6add129c5d9210ada25217abc130df0b7096ee02 ]

When fail to mmap events in task exit case, it misses to set 'err' to
-1; thus the testing will not report failure for it.

This patch sets 'err' to -1 when fails to mmap events, thus Perf tool
can report correct result.

Fixes: d723a55096b8 ("perf test: Add test case for checking number of EXIT events")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: http://lore.kernel.org/lkml/20191011091942.29841-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tests: Fix out of bounds memory access</title>
<updated>2019-12-17T18:56:23+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2019-11-07T02:02:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a88259db2765999277e09f949a5d5fac34612848'/>
<id>a88259db2765999277e09f949a5d5fac34612848</id>
<content type='text'>
commit af8490eb2b33684e26a0a927a9d93ae43cd08890 upstream.

The test case 'Read backward ring buffer' failed on 32-bit architectures
which were found by LKFT perf testing.  The test failed on arm32 x15
device, qemu_arm32, qemu_i386, and found intermittent failure on i386;
the failure log is as below:

  50: Read backward ring buffer                  :
  --- start ---
  test child forked, pid 510
  Using CPUID GenuineIntel-6-9E-9
  mmap size 1052672B
  mmap size 8192B
  Finished reading overwrite ring buffer: rewind
  free(): invalid next size (fast)
  test child interrupted
  ---- end ----
  Read backward ring buffer: FAILED!

The log hints there have issue for memory usage, thus free() reports
error 'invalid next size' and directly exit for the case.  Finally, this
issue is root caused as out of bounds memory access for the data array
'evsel-&gt;id'.

The backward ring buffer test invokes do_test() twice.  'evsel-&gt;id' is
allocated at the first call with the flow:

  test__backward_ring_buffer()
    `-&gt; do_test()
	  `-&gt; evlist__mmap()
	        `-&gt; evlist__mmap_ex()
	              `-&gt; perf_evsel__alloc_id()

So 'evsel-&gt;id' is allocated with one item, and it will be used in
function perf_evlist__id_add():

   evsel-&gt;id[0] = id
   evsel-&gt;ids   = 1

At the second call for do_test(), it skips to initialize 'evsel-&gt;id'
and reuses the array which is allocated in the first call.  But
'evsel-&gt;ids' contains the stale value.  Thus:

   evsel-&gt;id[1] = id    -&gt; out of bound access
   evsel-&gt;ids   = 2

To fix this issue, we will use evlist__open() and evlist__close() pair
functions to prepare and cleanup context for evlist; so 'evsel-&gt;id' and
'evsel-&gt;ids' can be initialized properly when invoke do_test() and avoid
the out of bounds memory access.

Fixes: ee74701ed8ad ("perf tests: Add test to check backward ring buffer")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Cc: stable@vger.kernel.org # v4.10+
Link: http://lore.kernel.org/lkml/20191107020244.2427-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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commit af8490eb2b33684e26a0a927a9d93ae43cd08890 upstream.

The test case 'Read backward ring buffer' failed on 32-bit architectures
which were found by LKFT perf testing.  The test failed on arm32 x15
device, qemu_arm32, qemu_i386, and found intermittent failure on i386;
the failure log is as below:

  50: Read backward ring buffer                  :
  --- start ---
  test child forked, pid 510
  Using CPUID GenuineIntel-6-9E-9
  mmap size 1052672B
  mmap size 8192B
  Finished reading overwrite ring buffer: rewind
  free(): invalid next size (fast)
  test child interrupted
  ---- end ----
  Read backward ring buffer: FAILED!

The log hints there have issue for memory usage, thus free() reports
error 'invalid next size' and directly exit for the case.  Finally, this
issue is root caused as out of bounds memory access for the data array
'evsel-&gt;id'.

The backward ring buffer test invokes do_test() twice.  'evsel-&gt;id' is
allocated at the first call with the flow:

  test__backward_ring_buffer()
    `-&gt; do_test()
	  `-&gt; evlist__mmap()
	        `-&gt; evlist__mmap_ex()
	              `-&gt; perf_evsel__alloc_id()

So 'evsel-&gt;id' is allocated with one item, and it will be used in
function perf_evlist__id_add():

   evsel-&gt;id[0] = id
   evsel-&gt;ids   = 1

At the second call for do_test(), it skips to initialize 'evsel-&gt;id'
and reuses the array which is allocated in the first call.  But
'evsel-&gt;ids' contains the stale value.  Thus:

   evsel-&gt;id[1] = id    -&gt; out of bound access
   evsel-&gt;ids   = 2

To fix this issue, we will use evlist__open() and evlist__close() pair
functions to prepare and cleanup context for evlist; so 'evsel-&gt;id' and
'evsel-&gt;ids' can be initialized properly when invoke do_test() and avoid
the out of bounds memory access.

Fixes: ee74701ed8ad ("perf tests: Add test to check backward ring buffer")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Cc: stable@vger.kernel.org # v4.10+
Link: http://lore.kernel.org/lkml/20191107020244.2427-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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