<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/tools/perf/tests/shell, branch v5.11</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v5.11</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v5.11'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2021-01-15T19:31:46Z</updated>
<entry>
<title>perf test: Fix shadow stat test for non-bash shells</title>
<updated>2021-01-15T19:31:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2021-01-14T05:06:09Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=a042a82ddbb3434f523c0671f5301d1fe796b4eb'/>
<id>urn:sha1:a042a82ddbb3434f523c0671f5301d1fe796b4eb</id>
<content type='text'>
It was using some bash-specific features and failed to parse when
running with a different shell like below:

  root@kbl-ppc:~/kbl-ws/perf-dev/lck-9077/acme.tmp/tools/perf# ./perf test 83 -vv
  83: perf stat metrics (shadow stat) test                            :
  --- start ---
  test child forked, pid 3922
  ./tests/shell/stat+shadow_stat.sh: 19: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 24: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 30: ./tests/shell/stat+shadow_stat.sh: [[: not found
  (standard_in) 2: syntax error
  ./tests/shell/stat+shadow_stat.sh: 36: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 19: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 24: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 30: ./tests/shell/stat+shadow_stat.sh: [[: not found
  (standard_in) 2: syntax error
  ./tests/shell/stat+shadow_stat.sh: 36: ./tests/shell/stat+shadow_stat.sh: [[: not found
  ./tests/shell/stat+shadow_stat.sh: 45: ./tests/shell/stat+shadow_stat.sh: declare: not found
  test child finished with -1
  ---- end ----
  perf stat metrics (shadow stat) test: FAILED!

Reported-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
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: David Laight &lt;david.laight@aculab.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/20210114050609.1258820-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Add support to read build id from compressed elf</title>
<updated>2020-12-17T17:36:17Z</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2020-12-14T10:54:48Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=47dce51acc330eefef5ea876f7707585b402282a'/>
<id>urn:sha1:47dce51acc330eefef5ea876f7707585b402282a</id>
<content type='text'>
Adding support to decompress file before reading build id.

Adding filename__read_build_id and change its current versions to
read_build_id.

Shutting down stderr output of perf list in the shell test:
  82: Check open filename arg using perf trace + vfs_getname          : Ok

because with decompression code in the place we the
filename__read_build_id function is more verbose in case
of error and the test did not account for that.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexei Budankov &lt;abudankov@huawei.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: 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: Stephane Eranian &lt;eranian@google.com&gt;
Link: http://lore.kernel.org/lkml/20201214105457.543111-7-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Add shadow stat test</title>
<updated>2020-11-30T11:58:26Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2020-11-27T04:14:04Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=94b69c615e4e2b04d1392d1193c72406ff9fd73e'/>
<id>urn:sha1:94b69c615e4e2b04d1392d1193c72406ff9fd73e</id>
<content type='text'>
It calculates IPC from the cycles and instruction counts and compares it
with the shadow stat for both global aggregation (default) and no
aggregation mode.

 $ perf stat -a -A -e cycles,instructions sleep 1

   Performance counter stats for 'system wide':

  CPU0   39,580,880      cycles
  CPU1   45,426,945      cycles
  CPU2   31,151,685      cycles
  CPU3   55,167,421      cycles
  CPU0   17,073,564      instructions      #    0.43  insn per cycle
  CPU1   34,955,764      instructions      #    0.77  insn per cycle
  CPU2   15,688,459      instructions      #    0.50  insn per cycle
  CPU3   34,699,217      instructions      #    0.63  insn per cycle

       1.003275495 seconds time elapsed

In this example, the 'insn per cycle' should be matched to the number
for each cpu.  For CPU2, 0.50 = 15,688,459 / 31,151,685 .

Committer testing:

  # perf test shadow
  78: perf stat metrics (shadow stat) test                            : Ok
  #

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&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: 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/20201127041404.390276-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Update branch sample pattern for cs-etm</title>
<updated>2020-11-12T20:55:42Z</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2020-11-10T06:34:17Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=dd94ac807a5e10e0b25b68397c473276905cca73'/>
<id>urn:sha1:dd94ac807a5e10e0b25b68397c473276905cca73</id>
<content type='text'>
Since the commit 943b69ac1884 ("perf parse-events: Set exclude_guest=1
for user-space counting"), 'exclude_guest=1' is set for user-space
counting; and the branch sample's modifier has been altered, the sample
event name has been changed from "branches:u:" to "branches:uH:", which
gives out info for "user-space and host counting".

But the cs-etm testing's regular expression cannot match the updated
branch sample event and leads to test failure.

This patch updates the branch sample pattern by using a more flexible
expression '.*' to match branch sample's modifiers, so that allows the
testing to work as expected.

Fixes: 943b69ac1884 ("perf parse-events: Set exclude_guest=1 for user-space counting")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: coresight ml &lt;coresight@lists.linaro.org&gt;
Cc: stable@kernel.org
Link: http://lore.kernel.org/lkml/20201110063417.14467-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Fix a typo in cs-etm testing</title>
<updated>2020-11-12T20:55:42Z</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2020-11-10T06:34:16Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=db2ac2e49e564c2b219c4b33d9903aa383334256'/>
<id>urn:sha1:db2ac2e49e564c2b219c4b33d9903aa383334256</id>
<content type='text'>
Fix a typo: s/devce_name/device_name.

Fixes: fe0aed19b266 ("perf test: Introduce script for Arm CoreSight testing")
Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: coresight ml &lt;coresight@lists.linaro.org&gt;
Cc: stable@kernel.org
Link: http://lore.kernel.org/lkml/20201110063417.14467-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Add build id shell test</title>
<updated>2020-10-14T14:28:52Z</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2020-10-13T19:24:41Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=78b2c50c5de990864f6180acea7a7037685b1b1b'/>
<id>urn:sha1:78b2c50c5de990864f6180acea7a7037685b1b1b</id>
<content type='text'>
Add a test for the build id cache that adds a binary with sha1 and md5
build ids and verifies it's added properly.

The test updates build id cache with 'perf record' and 'perf buildid-cache -a'.

Committer testing:

  # perf test "build id"
  82: build id cache operations                                       : Ok
  #
  # perf test -v "build id"
  82: build id cache operations                                       :
  --- start ---
  test child forked, pid 447218
  test binaries: /tmp/perf.ex.SHA1.B8I /tmp/perf.ex.MD5.7Nv
  Adding d1abc1eb7568358cf23c959566f23462461834d1 /tmp/perf.ex.SHA1.B8I: Ok
  build id: d1abc1eb7568358cf23c959566f23462461834d1
  link: /tmp/perf.debug.sS2/.build-id/d1/abc1eb7568358cf23c959566f23462461834d1
  file: /tmp/perf.debug.sS2/.build-id/d1/../../tmp/perf.ex.SHA1.B8I/d1abc1eb7568358cf23c959566f23462461834d1/elf
  OK for /tmp/perf.ex.SHA1.B8I
  Adding a50e350e97c43b4708d09bcd85ebfff7 /tmp/perf.ex.MD5.7Nv: Ok
  build id: a50e350e97c43b4708d09bcd85ebfff7
  link: /tmp/perf.debug.IuW/.build-id/a5/0e350e97c43b4708d09bcd85ebfff7
  file: /tmp/perf.debug.IuW/.build-id/a5/../../tmp/perf.ex.MD5.7Nv/a50e350e97c43b4708d09bcd85ebfff7/elf
  OK for /tmp/perf.ex.MD5.7Nv
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.034 MB /tmp/perf.data.xrH ]
  build id: d1abc1eb7568358cf23c959566f23462461834d1
  link: /tmp/perf.debug.eGR/.build-id/d1/abc1eb7568358cf23c959566f23462461834d1
  file: /tmp/perf.debug.eGR/.build-id/d1/../../tmp/perf.ex.SHA1.B8I/d1abc1eb7568358cf23c959566f23462461834d1/elf
  OK for /tmp/perf.ex.SHA1.B8I
  [ perf record: Woken up 2 times to write data ]
  [ perf record: Captured and wrote 0.034 MB /tmp/perf.data.cbE ]
  build id: a50e350e97c43b4708d09bcd85ebfff7
  link: /tmp/perf.debug.82t/.build-id/a5/0e350e97c43b4708d09bcd85ebfff7
  file: /tmp/perf.debug.82t/.build-id/a5/../../tmp/perf.ex.MD5.7Nv/a50e350e97c43b4708d09bcd85ebfff7/elf
  OK for /tmp/perf.ex.MD5.7Nv
  test child finished with 0
  ---- end ----
  build id cache operations: Ok
  #

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Acked-by: Ian Rogers &lt;irogers@google.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Link: https://lore.kernel.org/r/20201013192441.1299447-10-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Introduce script for Arm CoreSight testing</title>
<updated>2020-09-10T12:08:10Z</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2020-09-07T13:01:54Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=fe0aed19b266fdcbb5dd7abc9ac9b4a64ae82f91'/>
<id>urn:sha1:fe0aed19b266fdcbb5dd7abc9ac9b4a64ae82f91</id>
<content type='text'>
We need a simple method to test Perf with ARM CoreSight drivers, this
could be used for smoke testing when new patch is coming for perf or
CoreSight drivers, and we also can use the test to confirm if the
CoreSight has been enabled successfully on new platforms.

This patch introduces the shell script test_arm_coresight.sh which is
under the 'pert test' framework.  This script provides three testing
scenarios:

Test scenario 1: traverse all possible paths between source and sink

For traversing possible paths, simply to say, the testing rationale is
source oriented testing, it traverses every source (now only refers to
ETM device) and test its all possible sinks.  To search the complete
paths from one specific source to its sinks, this patch relies on the
sysfs '/sys/bus/coresight/devices/devX/out:Y' for depth-first search
(DFS) for iteration connected device nodes, if the output device is
detected as a sink device (the script will exclude TPIU device which can
not be supported for perf PMU), then it will test trace data recording
and decoding for it.

The script runs three output testings for every trace data:

- Test branch samples dumping with 'perf script' command;

- Test branch samples reporting with 'perf report' command;

- Use option '--itrace=i1000i' to insert synthesized instructions events
  and the script will check if perf can output the percentage value
  successfully based on the instruction samples.

Test scenario 2: system-wide test

For system-wide testing, it passes option '-a' to perf tool to enable
tracing on all CPUs, so it's hard to say which program will be traced.
But perf tool itself contributes much overload in this case, so it will
parse trace data and check if process 'perf' can be detected or not.

Test scenario 3: snapshot mode test.

For snapshot mode testing, it uses 'dd' command to launch a long running
program, so this can give chance to send signal -USR2; it will check the
captured trace data contains 'dd' related thread info or not.

If any test fails, it will report failure and directly exit with error.
This test will be only applied on a platform with PMU event 'cs_etm//',
otherwise will skip the testing.

Below is detailed usage for it:

  # cd $linux/tools/perf  -&gt; This is important so can use shell script
  # perf test list
    [...]
    70: probe libc's inet_pton &amp; backtrace it with ping
    71: Check Arm CoreSight trace data recording and synthesized samples
    72: Check open filename arg using perf trace + vfs_getname
    73: Zstd perf.data compression/decompression
    74: Add vfs_getname probe to get syscall args filenames
    75: Use vfs_getname probe to get syscall args filenames

  # perf test 71
    71: Check Arm CoreSight trace data recording and branch samples: Ok

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Reviewed-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Suzuki Poulouse &lt;suzuki.poulose@arm.com&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: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200907130154.9601-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf test: Allow multiple probes in record+script_probe_vfs_getname.sh</title>
<updated>2020-08-13T12:34:26Z</updated>
<author>
<name>Michael Petlan</name>
<email>mpetlan@redhat.com</email>
</author>
<published>2020-07-22T13:58:45Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=194cb6b50f57676130491341f321394bb16ee624'/>
<id>urn:sha1:194cb6b50f57676130491341f321394bb16ee624</id>
<content type='text'>
Sometimes when adding a kprobe by perf, it results in multiple probe
points, such as the following:

  # ./perf probe -l
    probe:vfs_getname    (on getname_flags:73@fs/namei.c with pathname)
    probe:vfs_getname_1  (on getname_flags:73@fs/namei.c with pathname)
    probe:vfs_getname_2  (on getname_flags:73@fs/namei.c with pathname)
  # cat /sys/kernel/debug/tracing/kprobe_events
  p:probe/vfs_getname _text+5501804 pathname=+0(+0(%gpr31)):string
  p:probe/vfs_getname_1 _text+5505388 pathname=+0(+0(%gpr31)):string
  p:probe/vfs_getname_2 _text+5508396 pathname=+0(+0(%gpr31)):string

In this test, we need to record all of them and expect any of them in
the perf-script output, since it's not clear which one will be used for
the desired syscall:

  # perf stat -e probe:vfs_getname\* -- touch /tmp/nic

   Performance counter stats for 'touch /tmp/nic':

                31      probe:vfs_getname_2
                 0      probe:vfs_getname_1
                 1      probe:vfs_getname
       0.001421826 seconds time elapsed

       0.001506000 seconds user
       0.000000000 seconds sys

If the test relies only on probe:vfs_getname, it might easily miss the
relevant data.

Signed-off-by: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
LPU-Reference: 20200722135845.29958-1-mpetlan@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tests: Fix test 68 zstd compression for s390</title>
<updated>2020-07-31T12:27:32Z</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2020-07-29T13:53:14Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=463538a383a27337cb83ae195e432a839a52d639'/>
<id>urn:sha1:463538a383a27337cb83ae195e432a839a52d639</id>
<content type='text'>
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;
</content>
</entry>
<entry>
<title>perf test: Fix test trace+probe_vfs_getname.sh on s390</title>
<updated>2020-02-18T13:13:28Z</updated>
<author>
<name>Thomas Richter</name>
<email>tmricht@linux.ibm.com</email>
</author>
<published>2020-02-17T10:21:11Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=2bbc83537614517730e9f2811195004b712de207'/>
<id>urn:sha1:2bbc83537614517730e9f2811195004b712de207</id>
<content type='text'>
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;
</content>
</entry>
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