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  1. 12 7月, 2017 1 次提交
    • A
      perf symbols: Accept zero as the kernel base address · 4b1303d0
      由 Arnaldo Carvalho de Melo 提交于 
      Which is the case in S/390, where symbols were not being resolved
because machine__get_kernel_start was only setting machine->kernel_start
when the just successfully loaded kernel symtab had its map->start set
to !0, when it was left at (1ULL << 63) assuming a partitioning of the
address space for user/kernel, which is not the case in S/390 nor in
Sparc.

So just check if map__load() was successfull and set
machine->kernel_start to zero, fixing kernel symbol resolution on S/390.

Test performed by Thomas:

 ----

  I like this patch. I have done a new build and removed all my debug output to start
  from scratch. Without your patch I get this:

  # Samples: 4  of event 'cpu-clock'
  # Event count (approx.): 1000000
  #
  # Children      Self  Command  Shared Object     Symbol
  # ........  ........  .......  ................  ........................
      75.00%     0.00%  true     [unknown]         [k] 0x00000000004bedda
              |
              ---0x4bedda
                 |
                 |--50.00%--0x42693a
                 |          |
                 |           --25.00%--0x2a72e0
                 |                     0x2af0ca
                 |                     0x3d1003fe4c0
                 |
                  --25.00%--0x4272bc
                            0x26fa84

  and with your patch (I just rebuilt the perf tool, nothing else and used the same
  perf.data file as input):

  # Samples: 4  of event 'cpu-clock'
  # Event count (approx.): 1000000
  #
  # Children      Self  Command  Shared Object               Symbol
  # ........  ........  .......  ..........................  ..................................
      75.00%     0.00%  true     [kernel.vmlinux]            [k] pgm_check_handler
              |
              ---pgm_check_handler
                 do_dat_exception
                 handle_mm_fault
                 __handle_mm_fault
                 filemap_map_pages
                 |
                 |--25.00%--rcu_read_lock_held
                 |          rcu_lockdep_current_cpu_online
                 |          0x3d1003ff4c0
                 |
                  --25.00%--lock_release

  Looks good to me....
 ----
Reported-and-Tested-by: NThomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zvonko Kosic <zvonko.kosic@de.ibm.com>
Link: http://lkml.kernel.org/n/tip-dk0n1uzmbe0tbthrpfqlx6bz@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4b1303d0
  3. 11 7月, 2017 3 次提交
  5. 04 7月, 2017 2 次提交
    • J
      perf unwind: Do not fail due to missing unwind support · 1934adf7
      由 Jiri Olsa 提交于 
      We currently fail the MMAP event processing if we don't have the MMAP
event's specific arch unwind support compiled in.

That's wrong and can lead to unresolved mmaps in report output for 32bit
binaries on 64bit server, like in this example on x86_64 server:

  $ cat ex.c
  int main(int argc, char **argv)
  {
          while (1) {}
  }
  $ gcc -o ex -m32 ex.c
  $ perf record ./ex
  ^C[ perf record: Woken up 2 times to write data ]
  [ perf record: Captured and wrote 0.371 MB perf.data (9322 samples) ]

Before:
  $ perf report --stdio

  SNIP

  # Overhead  Command  Shared Object     Symbol
  # ........  .......  ................  ......................
  #
     100.00%  ex       [unknown]         [.] 0x00000000080483de
       0.00%  ex       [unknown]         [.] 0x00000000f76dba4f
       0.00%  ex       [unknown]         [.] 0x00000000f76e4c11
       0.00%  ex       [unknown]         [.] 0x00000000f76daa30

After:
  $ perf report --stdio

  SNIP

  # Overhead  Command  Shared Object  Symbol
  # ........  .......  .............  ...............
  #
     100.00%  ex       ex             [.] main
       0.00%  ex       ld-2.24.so     [.] _dl_start
       0.00%  ex       ld-2.24.so     [.] do_lookup_x
       0.00%  ex       ld-2.24.so     [.] _start

The fix is not to fail, just warn if there's not unwind support compiled
in.
Reported-by: NMichael Lyle <mlyle@lyle.org>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170704131131.27508-1-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1934adf7
    • A
      perf evsel: Set attr.exclude_kernel when probing max attr.precise_ip · 97365e81
      由 Arnaldo Carvalho de Melo 提交于 
      We should set attr.exclude_kernel when probing for attr.precise_ip
level, otherwise !CAP_SYS_ADMIN users will not default to skidless
samples in capable hardware.

The increase in the paranoid level in commit 0161028b ("perf/core:
Change the default paranoia level to 2") broke this, fix it by excluding
kernel samples when probing.

Before:

  $ perf record usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.018 MB perf.data (6 samples) ]
  $ perf evlist -v
  cycles:u: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1

After:

  $ perf record usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.018 MB perf.data (8 samples) ]
  $ perf evlist -v
  cycles:ppp: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1, precise_ip: 3
                                                                                     ^^^^^^^^^^^^^
                                                                                     ^^^^^^^^^^^^^
                                                                                     ^^^^^^^^^^^^^
  $

To further clarify: we always set .exclude_kernel when non !CAP_SYS_ADMIN
users profile, its just on the attr.precise_ip probing that we weren't doing
so, fix it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 7f8d1ade ("perf tools: By default use the most precise "cycles" hw counter available")
Link: http://lkml.kernel.org/n/tip-t2qttwhbnua62o5gt75cueml@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      97365e81
  7. 30 6月, 2017 13 次提交
  9. 27 6月, 2017 16 次提交
  11. 26 6月, 2017 1 次提交
    • J
      perf machine: Fix segfault for kernel.kptr_restrict=2 · 3f938ee2
      由 Jiri Olsa 提交于 
      Michael reported the segfault when kernel.kptr_restrict=2 is set.

  $ perf record ls
  ...
  perf: Segmentation fault
  Obtained 16 stack frames.
  ./perf(dump_stack+0x2d) [0x5068df]
  ./perf(sighandler_dump_stack+0x2d) [0x5069bf]
  ./perf() [0x43e47b]
  /lib64/libc.so.6(+0x3594f) [0x7f762004794f]
  /lib64/libc.so.6(strlen+0x26) [0x7f762009ef86]
  /lib64/libc.so.6(__strdup+0xd) [0x7f762009ecbd]
  ./perf(maps__set_kallsyms_ref_reloc_sym+0x4d) [0x51590f]
  ./perf(machine__create_kernel_maps+0x136) [0x50a7de]
  ./perf(perf_session__create_kernel_maps+0x2c) [0x510a81]
  ./perf(perf_session__new+0x13d) [0x510e23]
  ./perf() [0x43fd61]
  ./perf(cmd_record+0x704) [0x441823]
  ./perf() [0x4bc1a0]
  ./perf() [0x4bc40d]
  ./perf() [0x4bc55f]
  ./perf(main+0x2d5) [0x4bc939]
  Segmentation fault (core dumped)

The reason is that with kernel.kptr_restrict=2, we don't get
the symbol from machine__get_running_kernel_start, which we
want to use in maps__set_kallsyms_ref_reloc_sym and we crash.

Check the symbol name value before calling
maps__set_kallsyms_ref_reloc_sym() and succeed without ref_reloc_sym
being set. It's safe because we check its existence before we use it.
Reported-by: NMichael Petlan <mpetlan@redhat.com>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170626095153.553-1-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      3f938ee2
  13. 23 6月, 2017 1 次提交
    • B
      perf probe: Fix probe definition for inlined functions · 7598f8bc
      由 Björn Töpel 提交于 
      In commit 613f050d ("perf probe: Fix to probe on gcc generated
functions in modules"), the offset from symbol is, incorrectly, added
to the trace point address. This leads to incorrect probe trace points
for inlined functions and when using relative line number on symbols.

Prior this patch:
  $ perf probe -m nf_nat -D in_range
  p:probe/in_range nf_nat:in_range.isra.9+0
  $ perf probe -m i40e -D i40e_clean_rx_irq
  p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2212
  $ perf probe -m i40e -D i40e_clean_rx_irq:16
  p:probe/i40e_clean_rx_irq i40e:i40e_lan_xmit_frame+626

After:
  $ perf probe -m nf_nat -D in_range
  p:probe/in_range nf_nat:in_range.isra.9+0
  $ perf probe -m i40e -D i40e_clean_rx_irq
  p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+1106
  $ perf probe -m i40e -D i40e_clean_rx_irq:16
  p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2665

Committer testing:

Using 'pfunct', a tool found in the 'dwarves' package [1], one can ask what are
the functions that while not being explicitely marked as inline, were inlined
by the compiler:

  # pfunct --cc_inlined /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko | head
  __ew32
  e1000_regdump
  e1000e_dump_ps_pages
  e1000_desc_unused
  e1000e_systim_to_hwtstamp
  e1000e_rx_hwtstamp
  e1000e_update_rdt_wa
  e1000e_update_tdt_wa
  e1000_put_txbuf
  e1000_consume_page

Then ask 'perf probe' to produce the kprobe_tracer probe definitions for two of
them:

  # perf probe -m e1000e -D e1000e_rx_hwtstamp
  p:probe/e1000e_rx_hwtstamp e1000e:e1000_receive_skb+74

  # perf probe -m e1000e -D e1000_consume_page
  p:probe/e1000_consume_page e1000e:e1000_clean_jumbo_rx_irq+876
  p:probe/e1000_consume_page_1 e1000e:e1000_clean_jumbo_rx_irq+1506
  p:probe/e1000_consume_page_2 e1000e:e1000_clean_rx_irq_ps+1074

Now lets concentrate on the 'e1000_consume_page' one, that was inlined twice in
e1000_clean_jumbo_rx_irq(), lets see what readelf says about the DWARF tags for
that function:

  $ readelf -wi /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko
  <SNIP>
  <1><13e27b>: Abbrev Number: 121 (DW_TAG_subprogram)
    <13e27c>   DW_AT_name        : (indirect string, offset: 0xa8945): e1000_clean_jumbo_rx_irq
    <13e287>   DW_AT_low_pc      : 0x17a30
  <3><13e6ef>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
    <13e6f0>   DW_AT_abstract_origin: <0x13ed2c>
    <13e6f4>   DW_AT_low_pc      : 0x17be6
  <SNIP>
  <1><13ed2c>: Abbrev Number: 142 (DW_TAG_subprogram)
     <13ed2e>   DW_AT_name        : (indirect string, offset: 0xa54c3): e1000_consume_page

So, the first time in e1000_clean_jumbo_rx_irq() where e1000_consume_page() is
inlined is at PC 0x17be6, which subtracted from e1000_clean_jumbo_rx_irq()'s
address, gives us the offset we should use in the probe definition:

  0x17be6 - 0x17a30 = 438

but above we have 876, which is twice as much.

Lets see the second inline expansion of e1000_consume_page() in
e1000_clean_jumbo_rx_irq():

  <3><13e86e>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
    <13e86f>   DW_AT_abstract_origin: <0x13ed2c>
    <13e873>   DW_AT_low_pc      : 0x17d21

  0x17d21 - 0x17a30 = 753

So we where adding it at twice the offset from the containing function as we
should.

And then after this patch:

  # perf probe -m e1000e -D e1000e_rx_hwtstamp
  p:probe/e1000e_rx_hwtstamp e1000e:e1000_receive_skb+37

  # perf probe -m e1000e -D e1000_consume_page
  p:probe/e1000_consume_page e1000e:e1000_clean_jumbo_rx_irq+438
  p:probe/e1000_consume_page_1 e1000e:e1000_clean_jumbo_rx_irq+753
  p:probe/e1000_consume_page_2 e1000e:e1000_clean_jumbo_rx_irq+1353
  #

Which matches the two first expansions and shows that because we were
doubling the offset it would spill over the next function:

  readelf -sw /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko
   673: 0000000000017a30  1626 FUNC    LOCAL  DEFAULT    2 e1000_clean_jumbo_rx_irq
   674: 0000000000018090  2013 FUNC    LOCAL  DEFAULT    2 e1000_clean_rx_irq_ps

This is the 3rd inline expansion of e1000_consume_page() in
e1000_clean_jumbo_rx_irq():

   <3><13ec77>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
    <13ec78>   DW_AT_abstract_origin: <0x13ed2c>
    <13ec7c>   DW_AT_low_pc      : 0x17f79

  0x17f79 - 0x17a30 = 1353

 So:

   0x17a30 + 2 * 1353 = 0x184c2

  And:

   0x184c2 - 0x18090 = 1074

Which explains the bogus third expansion for e1000_consume_page() to end up at:

   p:probe/e1000_consume_page_2 e1000e:e1000_clean_rx_irq_ps+1074

All fixed now :-)

[1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/Signed-off-by: NBjörn Töpel <bjorn.topel@intel.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NMagnus Karlsson <magnus.karlsson@intel.com>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 613f050d ("perf probe: Fix to probe on gcc generated functions in modules")
Link: http://lkml.kernel.org/r/20170621164134.5701-1-bjorn.topel@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      7598f8bc
  15. 21 6月, 2017 3 次提交