linux-stable.git/tools/perf/util/machine.c, branch linux-4.9.y

perf record: Fix module size on s390

2019-08-25T08:51:21+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 record: Fix wrong size in perf_record_mmap for last kernel module

2019-08-25T08:51:20+00:00

commit 9ad4652b66f19a60f07e63b942b80b5c2d7465bf upstream.

During work on perf report for s390 I ran into the following issue:

0 0x318 [0x78]: PERF_RECORD_MMAP -1/0:
        [0x3ff804d6990(0xfffffc007fb2966f) @ 0]:
        x /lib/modules/4.12.0perf1+/kernel/drivers/s390/net/qeth_l2.ko

This is a PERF_RECORD_MMAP entry of the perf.data file with an invalid
module size for qeth_l2.ko (the s390 ethernet device driver).

Even a mainframe does not have 0xfffffc007fb2966f bytes of main memory.

It turned out that this wrong size is created by the perf record
command.  What happens is this function call sequence from
__cmd_record():

  perf_session__new():
    perf_session__create_kernel_maps():
      machine__create_kernel_maps():
        machine__create_modules():   Creates map for all loaded kernel modules.
          modules__parse():   Reads /proc/modules and extracts module name and
                              load address (1st and last column)
            machine__create_module():   Called for every module found in /proc/modules.
                              Creates a new map for every module found and enters
                              module name and start address into the map. Since the
                              module end address is unknown it is set to zero.

This ends up with a kernel module map list sorted by module start
addresses.  All module end addresses are zero.

Last machine__create_kernel_maps() calls function map_groups__fixup_end().
This function iterates through the maps and assigns each map entry's
end address the successor map entry start address. The last entry of the
map group has no successor, so ~0 is used as end to consume the remaining
memory.

Later __cmd_record calls function record__synthesize() which in turn calls
perf_event__synthesize_kernel_mmap() and perf_event__synthesize_modules()
to create PERF_REPORT_MMAP entries into the perf.data file.

On s390 this results in the last module qeth_l2.ko
(which has highest start address, see module table:
        [root@s8360047 perf]# cat /proc/modules
        qeth_l2 86016 1 - Live 0x000003ff804d6000
        qeth 266240 1 qeth_l2, Live 0x000003ff80296000
        ccwgroup 24576 1 qeth, Live 0x000003ff80218000
        vmur 36864 0 - Live 0x000003ff80182000
        qdio 143360 2 qeth_l2,qeth, Live 0x000003ff80002000
        [root@s8360047 perf]# )
to be the last entry and its map has an end address of ~0.

When the PERF_RECORD_MMAP entry is created for kernel module qeth_l2.ko
its start address and length is written. The length is calculated in line:
    event->mmap.len   = pos->end - pos->start;
and results in 0xffffffffffffffff - 0x3ff804d6990(*) = 0xfffffc007fb2966f

(*) On s390 the module start address is actually determined by a __weak function
named arch__fix_module_text_start() in machine__create_module().

I think this improvable. We can use the module size (2nd column of /proc/modules)
to get each loaded kernel module size and calculate its end address.
Only for map entries which do not have a valid end address (end is still zero)
we can use the heuristic we have now, that is use successor start address or ~0.

Signed-off-by: Thomas-Mich Richter 
Reviewed-by: Arnaldo Carvalho de Melo 
Cc: Hendrik Brueckner 
Cc: Thomas-Mich Richter 
Cc: Zvonko Kosic 
LPU-Reference: 20170803134902.47207-2-tmricht@linux.vnet.ibm.com
Link: http://lkml.kernel.org/n/tip-nmoqij5b5vxx7rq2ckwu8iaj@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Cc: Daniel Daz 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

perf tools: Experiment with cppcheck

2016-10-03T14:24:13+00:00

Experimenting a bit using cppcheck[1], a static checker brought to my
attention by Colin, reducing the scope of some variables, reducing the
line of source code lines in the process:

  $ cppcheck --enable=style tools/perf/util/thread.c
  Checking tools/perf/util/thread.c...
  [tools/perf/util/thread.c:17]: (style) The scope of the variable 'leader' can be reduced.
  [tools/perf/util/thread.c:133]: (style) The scope of the variable 'err' can be reduced.
  [tools/perf/util/thread.c:273]: (style) The scope of the variable 'err' can be reduced.

Will continue later, but these are already useful, keep them.

1: https://sourceforge.net/p/cppcheck/wiki/Home/

Cc: Adrian Hunter 
Cc: Colin Ian King 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-ixws7lbycihhpmq9cc949ti6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Remove symbol_filter_t machinery

2016-09-05T14:14:50+00:00

We're not using it anymore, few users were, but we really could do
without it, simplify lots of functions by removing it.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-1zng8wdznn00iiz08bb7q3vn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Remove machine->symbol_filter and friends

2016-09-05T14:14:50+00:00

Including machines__set_symbol_filter(), not used anymore.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-7o1qgmrpvzuis4a9f0t8mnri@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf s390: Fix 'start' address of module's map

2016-07-26T19:46:12+00:00

At present, when creating module's map, perf gets 'start' address by
parsing '/proc/modules', but it's the module base address, it isn't the
start address of the '.text' section.

In most arches, it's OK. But for s390, it places 'GOT' and 'PLT'
relocations before '.text' section. So there exists an offset between
module base address and '.text' section, which will incur wrong symbol
resolution for modules.

Fix this bug by getting 'start' address of module's map from parsing
'/sys/module/[module name]/sections/.text', not from '/proc/modules'.

Signed-off-by: Song Shan Gong 
Acked-by: Jiri Olsa 
Cc: Christian Borntraeger 
Cc: David Ahern 
Link: http://lkml.kernel.org/r/1469070651-6447-2-git-send-email-gongss@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Destructors should accept NULL

2016-06-22T13:19:11+00:00

And do nothing, just like free(), to avoid having to test it in callers,
usually in error paths.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-q42gj3b3znhho9z1mrbo4jce@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'perf-core-for-mingo-20160607' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

2016-06-08T07:34:15+00:00

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Support cross unwinding, i.e. collecting '--call-graph dwarf' perf.data files
  in one machine and then doing analysis in another machine of a different
  hardware architecture. This enables, for instance, to do:

	perf record -a --call-graph dwarf

  on a x86-32 or aarch64 system and then do 'perf report' on it on a
  x86_64 workstation. (He Kuang)

- Fix crash in build_id_cache__kallsyms_path(), recent regression (Wang Nan)

Infrastructure changes:

- Make tools/lib/bpf use the IS_ERR return facility consistently and also stop
  using the _get_ term for non-reference count methods (Arnaldo Carvalho de Melo)

- 'perf config' refactorings (Taeung Song)

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar

perf unwind: Move unwind__prepare_access from thread_new into thread__insert_map

2016-06-07T15:08:52+00:00

To determine the libunwind methods to use, we should get the
32bit/64bit information from maps of a thread. When a thread is newly
created, the information is not prepared. This patch moves
unwind__prepare_access() into thread__insert_map() so we can get the
information we need from maps. Meanwhile, let thread__insert_map()
return value and show messages on error.

Signed-off-by: He Kuang 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Ekaterina Tumanova 
Cc: Josh Poimboeuf 
Cc: Kan Liang 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Sukadev Bhattiprolu 
Cc: Wang Nan 
Link: http://lkml.kernel.org/r/1464924803-22214-5-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-05-26T00:05:40+00:00

Pull perf updates from Ingo Molnar:
 "Mostly tooling and PMU driver fixes, but also a number of late updates
  such as the reworking of the call-chain size limiting logic to make
  call-graph recording more robust, plus tooling side changes for the
  new 'backwards ring-buffer' extension to the perf ring-buffer"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  perf record: Read from backward ring buffer
  perf record: Rename variable to make code clear
  perf record: Prevent reading invalid data in record__mmap_read
  perf evlist: Add API to pause/resume
  perf trace: Use the ptr->name beautifier as default for "filename" args
  perf trace: Use the fd->name beautifier as default for "fd" args
  perf report: Add srcline_from/to branch sort keys
  perf evsel: Record fd into perf_mmap
  perf evsel: Add overwrite attribute and check write_backward
  perf tools: Set buildid dir under symfs when --symfs is provided
  perf trace: Only auto set call-graph to "dwarf" when syscalls are being traced
  perf annotate: Sort list of recognised instructions
  perf annotate: Fix identification of ARM blt and bls instructions
  perf tools: Fix usage of max_stack sysctl
  perf callchain: Stop validating callchains by the max_stack sysctl
  perf trace: Fix exit_group() formatting
  perf top: Use machine->kptr_restrict_warned
  perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1
  perf machine: Do not bail out if not managing to read ref reloc symbol
  perf/x86/intel/p4: Trival indentation fix, remove space
  ...