linux-stable.git/tools/perf/util/machine.c, branch v4.19.78

perf record: Fix module size on s390

2019-08-16T08:12:41+00:00

commit 12a6d2940b5f02b4b9f71ce098e3bb02bc24a9ea upstream.

On s390 the modules loaded in memory have the text segment located after
the GOT and Relocation table. This can be seen with this output:

  [root@m35lp76 perf]# fgrep qeth /proc/modules
  qeth 151552 1 qeth_l2, Live 0x000003ff800b2000
  ...
  [root@m35lp76 perf]# cat /sys/module/qeth/sections/.text
  0x000003ff800b3990
  [root@m35lp76 perf]#

There is an offset of 0x1990 bytes. The size of the qeth module is
151552 bytes (0x25000 in hex).

The location of the GOT/relocation table at the beginning of a module is
unique to s390.

commit 203d8a4aa6ed ("perf s390: Fix 'start' address of module's map")
adjusts the start address of a module in the map structures, but does
not adjust the size of the modules. This leads to overlapping of module
maps as this example shows:

[root@m35lp76 perf] # ./perf report -D
     0 0 0xfb0 [0xa0]: PERF_RECORD_MMAP -1/0: [0x3ff800b3990(0x25000)
          @ 0]:  x /lib/modules/.../qeth.ko.xz
     0 0 0x1050 [0xb0]: PERF_RECORD_MMAP -1/0: [0x3ff800d85a0(0x8000)
          @ 0]:  x /lib/modules/.../ip6_tables.ko.xz

The module qeth.ko has an adjusted start address modified to b3990, but
its size is unchanged and the module ends at 0x3ff800d8990.  This end
address overlaps with the next modules start address of 0x3ff800d85a0.

When the size of the leading GOT/Relocation table stored in the
beginning of the text segment (0x1990 bytes) is subtracted from module
qeth end address, there are no overlaps anymore:

   0x3ff800d8990 - 0x1990 = 0x0x3ff800d7000

which is the same as

   0x3ff800b2000 + 0x25000 = 0x0x3ff800d7000.

To fix this issue, also adjust the modules size in function
arch__fix_module_text_start(). Add another function parameter named size
and reduce the size of the module when the text segment start address is
changed.

Output after:
     0 0 0xfb0 [0xa0]: PERF_RECORD_MMAP -1/0: [0x3ff800b3990(0x23670)
          @ 0]:  x /lib/modules/.../qeth.ko.xz
     0 0 0x1050 [0xb0]: PERF_RECORD_MMAP -1/0: [0x3ff800d85a0(0x7a60)
          @ 0]:  x /lib/modules/.../ip6_tables.ko.xz

Reported-by: Stefan Liebler 
Signed-off-by: Thomas Richter 
Acked-by: Heiko Carstens 
Cc: Hendrik Brueckner 
Cc: Vasily Gorbik 
Cc: stable@vger.kernel.org
Fixes: 203d8a4aa6ed ("perf s390: Fix 'start' address of module's map")
Link: http://lkml.kernel.org/r/20190724122703.3996-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf machine: Update kernel map address and re-order properly

2019-05-04T07:20:22+00:00

[ Upstream commit 977c7a6d1e263ff1d755f28595b99e4bc0c48a9f ]

Since commit 1fb87b8e9599 ("perf machine: Don't search for active kernel
start in __machine__create_kernel_maps"), the __machine__create_kernel_maps()
just create a map what start and end are both zero. Though the address will be
updated later, the order of map in the rbtree may be incorrect.

The commit ee05d21791db ("perf machine: Set main kernel end address properly")
fixed the logic in machine__create_kernel_maps(), but it's still wrong in
function machine__process_kernel_mmap_event().

To reproduce this issue, we need an environment which the module address
is before the kernel text segment. I tested it on an aarch64 machine with
kernel 4.19.25:

  [root@localhost hulk]# grep _stext /proc/kallsyms
  ffff000008081000 T _stext
  [root@localhost hulk]# grep _etext /proc/kallsyms
  ffff000009780000 R _etext
  [root@localhost hulk]# tail /proc/modules
  hisi_sas_v2_hw 77824 0 - Live 0xffff00000191d000
  nvme_core 126976 7 nvme, Live 0xffff0000018b6000
  mdio 20480 1 ixgbe, Live 0xffff0000018ab000
  hisi_sas_main 106496 1 hisi_sas_v2_hw, Live 0xffff000001861000
  hns_mdio 20480 2 - Live 0xffff000001822000
  hnae 28672 3 hns_dsaf,hns_enet_drv, Live 0xffff000001815000
  dm_mirror 40960 0 - Live 0xffff000001804000
  dm_region_hash 32768 1 dm_mirror, Live 0xffff0000017f5000
  dm_log 32768 2 dm_mirror,dm_region_hash, Live 0xffff0000017e7000
  dm_mod 315392 17 dm_mirror,dm_log, Live 0xffff000001780000
  [root@localhost hulk]#

Before fix:

  [root@localhost bin]# perf record sleep 3
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.011 MB perf.data (9 samples) ]
  [root@localhost bin]# perf buildid-list -i perf.data
  4c4e46c971ca935f781e603a09b52a92e8bdfee8 [vdso]
  [root@localhost bin]# perf buildid-list -i perf.data -H
  0000000000000000000000000000000000000000 /proc/kcore
  [root@localhost bin]#

After fix:

  [root@localhost tools]# ./perf/perf record sleep 3
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.011 MB perf.data (9 samples) ]
  [root@localhost tools]# ./perf/perf buildid-list -i perf.data
  28a6c690262896dbd1b5e1011ed81623e6db0610 [kernel.kallsyms]
  106c14ce6e4acea3453e484dc604d66666f08a2f [vdso]
  [root@localhost tools]# ./perf/perf buildid-list -i perf.data -H
  28a6c690262896dbd1b5e1011ed81623e6db0610 /proc/kcore

Signed-off-by: Wei Li 
Acked-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Hanjun Guo 
Cc: Kim Phillips 
Cc: Li Bin 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20190228092003.34071-1-liwei391@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin (Microsoft)

perf report: Fix wrong iteration count in --branch-history

2019-02-20T09:25:39+00:00

[ Upstream commit a3366db06bb656cef2e03f30f780d93059bcc594 ]

By calculating the removed loops, we can get the iteration count.

But the iteration count could be reported incorrectly, reporting
impossibly high counts.

That's because previous code uses the number of removed LBR entries for
the iteration count. That's not good. Fix this by increasing the
iteration count when a loop is detected.

When matching the chain, the iteration count would be added up, finally we need
to compute the average value when printing out.

For example,

  $ perf report --branch-history --stdio --no-children

Before:

  ---f2 +0
     |
     |--33.62%--f1 +9 (cycles:1)
     |          f1 +0
     |          main +22 (cycles:1)
     |          main +17
     |          main +38 (cycles:1)
     |          main +27
     |          f1 +26 (cycles:1)
     |          f1 +24
     |          f2 +27 (cycles:7)
     |          f2 +0
     |          f1 +19 (cycles:1)
     |          f1 +14
     |          f2 +27 (cycles:11)
     |          f2 +0
     |          f1 +9 (cycles:1 iter:2968 avg_cycles:3)
     |          f1 +0
     |          main +22 (cycles:1 iter:2968 avg_cycles:3)
     |          main +17
     |          main +38 (cycles:1 iter:2968 avg_cycles:3)

2968 is an impossible high iteration count and avg_cycles is too small.

After:

  ---f2 +0
     |
     |--33.62%--f1 +9 (cycles:1)
     |          f1 +0
     |          main +22 (cycles:1)
     |          main +17
     |          main +38 (cycles:1)
     |          main +27
     |          f1 +26 (cycles:1)
     |          f1 +24
     |          f2 +27 (cycles:7)
     |          f2 +0
     |          f1 +19 (cycles:1)
     |          f1 +14
     |          f2 +27 (cycles:11)
     |          f2 +0
     |          f1 +9 (cycles:1 iter:1 avg_cycles:23)
     |          f1 +0
     |          main +22 (cycles:1 iter:1 avg_cycles:23)
     |          main +17
     |          main +38 (cycles:1 iter:1 avg_cycles:23)

avg_cycles:23 is the average cycles of this iteration.

Fixes: c4ee06251d42 ("perf report: Calculate the average cycles of iterations")

Signed-off-by: Jin Yao 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1546582230-17507-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf thread: Add fallback functions for cases where cpumode is insufficient

2019-01-09T16:38:42+00:00

commit 8e80ad9983caeee09c3a0a1a37e05bff93becce4 upstream.

For branch stacks or branch samples, the sample cpumode might not be
correct because it applies only to the sample 'ip' and not necessary to
'addr' or branch stack addresses. Add fallback functions that can be
used to deal with those cases

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: David S. Miller 
Cc: Jiri Olsa 
Cc: Leo Yan 
Cc: Mathieu Poirier 
Cc: stable@vger.kernel.org # 4.19
Link: http://lkml.kernel.org/r/20181106210712.12098-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf callchain: Honour the ordering of PERF_CONTEXT_{USER,KERNEL,etc}

2018-11-21T08:19:19+00:00

commit e9024d519d892b38176cafd46f68a7cdddd77412 upstream.

When processing using 'perf report -g caller', which is the default, we
ended up reverting the callchain entries received from the kernel, but
simply reverting throws away the information that tells that from a
point onwards the addresses are for userspace, kernel, guest kernel,
guest user, hypervisor.

The idea is that if we are walking backwards, for each cluster of
non-cpumode entries we have to first scan backwards for the next one and
use that for the cluster.

This seems silly and more expensive than it needs to be but it is enough
for a initial fix.

The code here is really complicated because it is intimately intertwined
with the lbr and branch handling, as well as this callchain order,
further fixes will be needed to properly take into account the cpumode
in those cases.

Another problem with ORDER_CALLER is that the NULL "0" IP that is at the
end of most callchains shows up at the top of the histogram because
every callchain contains it and with ORDER_CALLER it is the first entry.

Signed-off-by: David S. Miller 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Souvik Banerjee 
Cc: Wang Nan 
Cc: stable@vger.kernel.org # 4.19
Link: https://lkml.kernel.org/n/tip-2wt3ayp6j2y2f2xowixa8y6y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf record: Use unmapped IP for inline callchain cursors

2018-10-05T14:18:09+00:00

Only use the mapped IP to find inline frames, but keep using the
unmapped IP for the callchain cursor. This ensures we properly show the
unmapped IP when displaying a frame we received via the
dso__parse_addr_inlines API for a module which does not contain
sufficient debug symbols to show the srcline.

This is another follow-up to commit 19610184693c ("perf script: Show
virtual addresses instead of offsets").

Signed-off-by: Milian Wolff 
Acked-by: Jiri Olsa 
Tested-by: Ravi Bangoria 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Jin Yao 
Cc: Namhyung Kim 
Cc: Sandipan Das 
Fixes: 19610184693c ("perf script: Show virtual addresses instead of offsets")
Link: http://lkml.kernel.org/r/20180926135207.30263-2-milian.wolff@kdab.com
Link: http://lkml.kernel.org/r/20181002073949.3297-1-milian.wolff@kdab.com
[ Squashed a fix from Milian for a problem reported by Ravi, fixed up space damage ]
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Don't try to map ip to invalid map

2018-09-27T19:05:43+00:00

Fixes a crash when the report encounters an address that could not be
associated with an mmaped region:

  #0  0x00005555557bdc4a in callchain_srcline (ip=, sym=0x0, map=0x0) at util/machine.c:2329
  #1  unwind_entry (entry=entry@entry=0x7fffffff9180, arg=arg@entry=0x7ffff5642498) at util/machine.c:2329
  #2  0x00005555558370af in entry (arg=0x7ffff5642498, cb=0x5555557bdb50 , thread=, ip=18446744073709551615) at util/unwind-libunwind-local.c:586
  #3  get_entries (ui=ui@entry=0x7fffffff9620, cb=0x5555557bdb50 , arg=0x7ffff5642498, max_stack=) at util/unwind-libunwind-local.c:703
  #4  0x0000555555837192 in _unwind__get_entries (cb=, arg=, thread=, data=, max_stack=) at util/unwind-libunwind-local.c:725
  #5  0x00005555557c310f in thread__resolve_callchain_unwind (max_stack=127, sample=0x7fffffff9830, evsel=0x555555c7b3b0, cursor=0x7ffff5642498, thread=0x555555c7f6f0) at util/machine.c:2351
  #6  thread__resolve_callchain (thread=0x555555c7f6f0, cursor=0x7ffff5642498, evsel=0x555555c7b3b0, sample=0x7fffffff9830, parent=0x7fffffff97b8, root_al=0x7fffffff9750, max_stack=127) at util/machine.c:2378
  #7  0x00005555557ba4ee in sample__resolve_callchain (sample=, cursor=, parent=parent@entry=0x7fffffff97b8, evsel=, al=al@entry=0x7fffffff9750,
      max_stack=) at util/callchain.c:1085

Signed-off-by: Milian Wolff 
Tested-by: Sandipan Das 
Acked-by: Jiri Olsa 
Cc: Jin Yao 
Cc: Namhyung Kim 
Fixes: 2a9d5050dc84 ("perf script: Show correct offsets for DWARF-based unwinding")
Link: http://lkml.kernel.org/r/20180926135207.30263-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Store compression id into struct dso

2018-08-20T11:54:59+00:00

Add comp to 'struct dso' to hold the compression index.  It will be used
in the following patches.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180817094813.15086-8-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Use last_match threads cache only in single thread mode

2018-07-24T17:53:52+00:00

There's an issue with using threads::last_match in multithread mode
which is enabled during the perf top synthesize. It might crash with
following assertion:

  perf: ...include/linux/refcount.h:109: refcount_inc:
        Assertion `!(!refcount_inc_not_zero(r))' failed.

The gdb backtrace looks like this:

  0x00007ffff50839fb in raise () from /lib64/libc.so.6
  (gdb)
  #0  0x00007ffff50839fb in raise () from /lib64/libc.so.6
  #1  0x00007ffff5085800 in abort () from /lib64/libc.so.6
  #2  0x00007ffff507c0da in __assert_fail_base () from /lib64/libc.so.6
  #3  0x00007ffff507c152 in __assert_fail () from /lib64/libc.so.6
  #4  0x0000000000535ff9 in refcount_inc (r=0x7fffe8009a70)
      at ...include/linux/refcount.h:109
  #5  0x0000000000536771 in thread__get (thread=0x7fffe8009a40)
      at util/thread.c:115
  #6  0x0000000000523cd0 in ____machine__findnew_thread (machine=0xbfde38,
      threads=0xbfdf28, pid=2, tid=2, create=true) at util/machine.c:432
  #7  0x0000000000523eb4 in __machine__findnew_thread (machine=0xbfde38,
      pid=2, tid=2) at util/machine.c:489
  #8  0x0000000000523f24 in machine__findnew_thread (machine=0xbfde38,
      pid=2, tid=2) at util/machine.c:499
  #9  0x0000000000526fbe in machine__process_fork_event (machine=0xbfde38,
  ...

The failing assertion is this one:

  REFCOUNT_WARN(!refcount_inc_not_zero(r), ...

the problem is that we don't serialize access to threads::last_match.
We serialize the access to the threads tree, but we don't care how's
threads::last_match being accessed. Both locked/unlocked paths use
that data and can set it. In multithreaded mode we can end up with
invalid object in thread__get call, like in following paths race:

  thread 1
    ...
    machine__findnew_thread
      down_write(&threads->lock);
      __machine__findnew_thread
        ____machine__findnew_thread
          th = threads->last_match;
          if (th->tid == tid) {
            thread__get

  thread 2
    ...
    machine__find_thread
      down_read(&threads->lock);
      __machine__findnew_thread
        ____machine__findnew_thread
          th = threads->last_match;
          if (th->tid == tid) {
            thread__get

  thread 3
    ...
    machine__process_fork_event
      machine__remove_thread
        __machine__remove_thread
          threads->last_match = NULL
          thread__put
      thread__put

Thread 1 and 2 might got stale last_match, before thread 3 clears
it. Thread 1 and 2 then race with thread 3's thread__put and they
might trigger the refcnt == 0 assertion above.

The patch is disabling the last_match cache for multiple thread
mode. It was originally meant for single thread scenarios, where
it's common to have multiple sequential searches of the same
thread.

In multithread mode this does not make sense, because top's threads
processes different /proc entries and so the 'struct threads' object
is queried for various threads. Moreover we'd need to add more locks
to make it work.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Kan Liang 
Cc: Lukasz Odzioba 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/20180719143345.12963-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add threads__set_last_match function

2018-07-24T17:53:42+00:00

Separating threads::last_match cache set into separate
threads__set_last_match function.  This will be useful in following
patch.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Kan Liang 
Cc: Lukasz Odzioba 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/20180719143345.12963-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo