linux-stable.git/tools/perf/util/machine.c, branch linux-4.1.y

perf buildid-list: Fix segfault when show DSOs with hits

2015-04-10T13:13:59+00:00

commit: f3b623b8490a ("perf tools: Reference count struct thread")
appends every thread->node to dead_threads in machine__remove_thread()
and list_del_init() this node in thread__put().

perf_event__exit_del_thread() releases thread wihout using
machine__remove_thread(), and causes a NULL pointer crash when
list_del_init(&thread->node) is called. Fix this by using
machine_remove_thread() instead of using thread__put() directly.

This problem can be reproduced as following:

  $ perf record ls
  $ perf buildid-list --with-hits
  [ 3874.195070] perf[1018]: segfault at 0 ip 00000000004b0b15 sp
  00007ffc35b44780 error 6 in perf[400000+166000]
  Segmentation fault

After this patch:
  $ perf record ls
  $ perf buildid-list --with-hits
  bc23e7c3281e542650ba4324421d6acf78f4c23e /proc/kcore
  643324cb0e969f30c56d660f167f84a150845511 [vdso]
  0000000000000000000000000000000000000000 /bin/busybox
  ...

Signed-off-by: He Kuang 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1428658500-6483-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

perf kmaps: Check kmaps to make code more robust

2015-04-08T12:07:03+00:00

This patch add checks in places where map__kmap is used to get kmaps
from struct kmap.

Error messages are added at map__kmap to warn invalid accessing of kmap
(for the case of !map->dso->kernel, kmap(map) does not exists at all).

Also, introduces map__kmaps() to warn uninitialized kmaps.

Reviewed-by: Ingo Molnar 
Signed-off-by: Wang Nan 
Cc: pi3orama@163.com
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Zefan Li 
Link: http://lkml.kernel.org/r/1428394966-131044-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Fix kernel symbol resolution by remembering the cpumode

2015-03-31T20:52:17+00:00

Commit 2e77784bb7d8 ("perf callchain: Move cpumode resolve code to
add_callchain_ip") promised "No change in behavior.".

As this commit breaks callchains on s390x (symbols not getting resolved,
observed when profiling the kernel), this statement is wrong. The cpumode
must be kept when iterating over all ips, otherwise the default
(PERF_RECORD_MISC_USER) will be used by error.

Signed-off-by: David Hildenbrand 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: David Hildenbrand 
Cc: Hendrik Brueckner 
Cc: Kan Liang 
Cc: Martin Schwidefsky 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1427703060-59883-1-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Try to lookup kernel module map before creating one

2015-03-23T15:46:51+00:00

Currently we assume machine__new_module is called only once for each
module so we create its map&dso unconditionally.

However it's possible that it's called multiple times for same module.
Like for perf record:

  1) via machine__create_module during machine init
  2) via kernel MMAP event processing

Trying to lookup kernel module map before creating one.

Signed-off-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-kx76xfqpnrpho5hdaapbqm09@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove compressed argument from is_kernel_module

2015-03-23T15:39:30+00:00

We no longer need the 'compressed' argument, because all
current users use 'NULL' for it.

Signed-off-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-d72q2s7ggbmy2yzhumux4zzw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use kmod_path__parse in map_groups__set_modules_path_dir

2015-03-23T14:43:25+00:00

Replacing the file name parsing with kmod_path__parse
and moving the dso update into new separate function.

Signed-off-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-q0ed76ajcyoaofotntrg5sla@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use kmod_pathparse for machinenew_dso

2015-03-21T17:58:07+00:00

Using kmod_path__parse to get the module name and update the dso short
name within machine__new_dso function.

This way it's done only first time when dso is created, unlike the
current way when we update it all the time we process memory map of the
kernel module.

Signed-off-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-8gjmt1ggf5ls1xkk7qi2ko4k@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add machine__module_dso function

2015-03-21T17:55:48+00:00

Separate the dso object addition and update when adding new kernel
module.

Currently we update dso's symtab_type any time we find it in the list,
because we can't distinguish between new and found dso from
__dsos__findnew function.

Adding machine__module_dso that separates finding and adding new dso
objects, so there's no superfluous update of dso.

Signed-off-by: Jiri Olsa 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-uvqgs5tyq4wssnq6fm43hgvk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Reference count struct thread

2015-03-03T03:17:08+00:00

We need to do that to stop accumulating entries in the dead_threads
linked list, i.e. we were keeping references to threads in struct hists
that continue to exist even after a thread exited and was removed from
the machine threads rbtree.

We still keep the dead_threads list, but just for debugging, allowing us
to iterate at any given point over the threads that still are referenced
by things like struct hist_entry.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-3ejvfyed0r7ue61dkurzjux4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Construct LBR call chain

2015-02-18T16:16:18+00:00

LBR call stack only has user-space callchains. It is output in the
PERF_SAMPLE_BRANCH_STACK data format. For kernel callchains, it's
still in the form of PERF_SAMPLE_CALLCHAIN.

The perf tool has to handle both data sources to construct a
complete callstack.

For the "perf report -D" option, both lbr and fp information will be
displayed.

A new call chain recording option "lbr" is introduced into the perf
tool for LBR call stack. The user can use --call-graph lbr to get
the call stack information from hardware.

Here are some examples.

When profiling bc(1) on Fedora 19:

  echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph lbr bc -l < cmd

If enabling LBR, perf report output looks like:

    50.36%       bc  bc                 [.] bc_divide
                 |
                 --- bc_divide
                     execute
                     run_code
                     yyparse
                     main
                     __libc_start_main
                     _start
    33.66%       bc  bc                 [.] _one_mult
                 |
                 --- _one_mult
                     bc_divide
                     execute
                     run_code
                     yyparse
                     main
                     __libc_start_main
                     _start
     7.62%       bc  bc                 [.] _bc_do_add
                 |
                 --- _bc_do_add
                    |
                    |--99.89%-- 0x2000186a8
                     --0.11%-- [...]
     6.83%       bc  bc                 [.] _bc_do_sub
                 |
                 --- _bc_do_sub
                    |
                    |--99.94%-- bc_add
                    |          execute
                    |          run_code
                    |          yyparse
                    |          main
                    |          __libc_start_main
                    |          _start
                     --0.06%-- [...]
     0.46%       bc  libc-2.17.so       [.] __memset_sse2
                 |
                 --- __memset_sse2
                    |
                    |--54.13%-- bc_new_num
                    |          |
                    |          |--51.00%-- bc_divide
                    |          |          execute
                    |          |          run_code
                    |          |          yyparse
                    |          |          main
                    |          |          __libc_start_main
                    |          |          _start
                    |          |
                    |          |--30.46%-- _bc_do_sub
                    |          |          bc_add
                    |          |          execute
                    |          |          run_code
                    |          |          yyparse
                    |          |          main
                    |          |          __libc_start_main
                    |          |          _start
                    |          |
                    |           --18.55%-- _bc_do_add
                    |                     bc_add
                    |                     execute
                    |                     run_code
                    |                     yyparse
                    |                     main
                    |                     __libc_start_main
                    |                     _start
                    |
                     --45.87%-- bc_divide
                               execute
                               run_code
                               yyparse
                               main
                               __libc_start_main
                               _start

If using FP, perf report output looks like:

  echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph fp bc -l < cmd

    50.49%       bc  bc                 [.] bc_divide
                 |
                 --- bc_divide
    33.57%       bc  bc                 [.] _one_mult
                 |
                 --- _one_mult
     7.61%       bc  bc                 [.] _bc_do_add
                 |
                 --- _bc_do_add
                     0x2000186a8
     6.88%       bc  bc                 [.] _bc_do_sub
                 |
                 --- _bc_do_sub
     0.42%       bc  libc-2.17.so       [.] __memcpy_ssse3_back
                 |
                 --- __memcpy_ssse3_back

If using LBR, perf report -D output looks like:

3458145275743 0x2fd750 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x2): 9748/9748: 0x408ea8 period: 609644 addr: 0
... LBR call chain: nr:8
.....  0: fffffffffffffe00
.....  1: 0000000000408e50
.....  2: 000000000040a458
.....  3: 000000000040562e
.....  4: 0000000000408590
.....  5: 00000000004022c0
.....  6: 00000000004015dd
.....  7: 0000003d1cc21b43
... FP chain: nr:2
.....  0: fffffffffffffe00
.....  1: 0000000000408ea8
 ... thread: bc:9748
 ...... dso: /usr/bin/bc

The LBR call stack has the following known limitations:

 - Zero length calls are not filtered out by the hardware

 - Exception handing such as setjmp/longjmp will have calls/returns not
   match

 - Pushing different return address onto the stack will have
   calls/returns not match

 - If callstack is deeper than the LBR, only the last entries are
   captured

Tested-by: Jiri Olsa 
Signed-off-by: Kan Liang 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Simon Que 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1420482185-29830-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar