On ubuntu the internal kernel version code is different from what can
be retrived from uname:

 $ uname -r
 4.4.0-47-generic
 $ cat /lib/modules/`uname -r`/build/include/generated/uapi/linux/version.h
 #define LINUX_VERSION_CODE 263192
 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
 $ cat /lib/modules/`uname -r`/build/include/generated/utsrelease.h
 #define UTS_RELEASE "4.4.0-47-generic"
 #define UTS_UBUNTU_RELEASE_ABI 47
 $ cat /proc/version_signature
 Ubuntu 4.4.0-47.68-generic 4.4.24

The macro LINUX_VERSION_CODE is set to 4.4.24 (263192 == 0x40418), but
`uname -r` reports 4.4.0.

This mismatch causes LINUX_VERSION_CODE macro passed to BPF script become
an incorrect value, results in magic failure in BPF loading:

 $ sudo ./buildperf/perf record -e ./tools/perf/tests/bpf-script-example.c ls
 event syntax error: './tools/perf/tests/bpf-script-example.c'
                      \___ Failed to load program for unknown reason

According to Ubuntu document (https://wiki.ubuntu.com/Kernel/FAQ), the
correct kernel version can be retrived through /proc/version_signature, which
is ubuntu specific.

This patch checks the existance of /proc/version_signature, and returns
version number through parsing this file instead of uname. Version string
is untouched (value returns from uname) because `uname -r` is required
to be consistence with path of kbuild directory in /lib/module.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161115040617.69788-2-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

When it records callchains, they will always have 2 scheduler functions
(__schedule + schedule or __schedule + preempt_schedule) and get
ignored.  So it should collect 2 more functions to show the expected
number of callchains to user.

Committer Notes:

Example of final result, using the same perf.data file as in the
previous cset comment, but this time redirecting the output of 'perf
sched timehist' to a file instead of copy'n'pasting from xterm:

  [root@jouet experimental]# perf sched timehist > /tmp/bla
  [root@jouet experimental]# cat /tmp/bla
      time  cpu task name        wait time sch delay run time
                 [tid/pid]            (msec) (msec) (msec)
  -------- ----  -------------------- ------ ------ -----
  6.494998 [01] <idle>                0.000  0.000  0.000
  6.495027 [02] perf[519]             0.000  0.000  0.000 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
  6.495096 [03] <idle>                0.000  0.000  0.000
  6.495100 [03] rcuos/0[9]            0.000  0.005  0.003 rcu_nocb_kthread <- kthread <- ret_from_fork
  6.495113 [01] perf[520]             0.000  0.008  0.114 preempt_schedule_common <- _cond_resched <- wait_for_completion <- stop_one_cpu <- sched_exec <- do_execveat_common.isra.35
  6.495121 [00] <idle>                0.000  0.000  0.000
  6.495129 [01] migration/1[17]       0.000  0.003  0.016 smpboot_thread_fn <- kthread <- ret_from_fork
  6.496085 [02] <idle>                0.000  0.000  1.057
  6.496096 [02] kworker/u16:1[31169]  0.000  0.004  0.011 worker_thread <- kthread <- ret_from_fork
  6.496096 [03] <idle>                0.003  0.000  0.996
  6.496169 [02] <idle>                0.011  0.000  0.072
  6.496171 [00] ls[520]               0.008  0.000  1.049 do_exit <- do_group_exit <- [unknown] <- entry_SYSCALL_64_fastpath
  6.496172 [03] gnome-terminal-[4391] 0.000  0.003  0.076 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_timeout <- do_sys_poll <- sys_poll
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161124011114.7102-3-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The sched_switch event always captured from the scheduler function.  So
it'd be great omit them from the callchain.  This patch marks the
functions to be omitted by later patch.

Committer notes:

Testing it:

Before:

  [root@jouet experimental]# perf sched record -g ls
  Dockerfile  perf.data  x-mips64
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 1.355 MB perf.data (29 samples) ]
  [root@jouet experimental]# perf sched timehist
      time  cpu  task name         wait time sch delay run time
                 [tid/pid]             (msec) (msec) (msec)
  ----------- -----  ----------------- ------ ------ ------
  6.494998 [001] <idle>                0.000  0.000  0.000
  6.495027 [002] perf[519]             0.000  0.000  0.000 __schedule <- schedule <- schedule_hrtimeout_range_clock <- schedule_hrtimeou
  6.495096 [003] <idle>                0.000  0.000  0.000
  6.495100 [003] rcuos/0[9]            0.000  0.005  0.003 __schedule <- schedule <- rcu_nocb_kthread <- kthread <- ret_from_fork
  6.495113 [001] perf[520]             0.000  0.008  0.114 __schedule <- preempt_schedule_common <- _cond_resched <- wait_for_completion
  6.495121 [000] <idle>                0.000  0.000  0.000
  6.495129 [001] migration/1[17]       0.000  0.003  0.016 __schedule <- schedule <- smpboot_thread_fn <- kthread <- ret_from_fork
  6.496085 [002] <idle>                0.000  0.000  1.057
  6.496096 [002] kworker/u16:1[31169]  0.000  0.004  0.011 __schedule <- schedule <- worker_thread <- kthread <- ret_from_fork
  6.496096 [003] <idle>                0.003  0.000  0.996
  6.496169 [002] <idle>                0.011  0.000  0.072
  6.496171 [000] ls[520]               0.008  0.000  1.049 __schedule <- schedule <- do_exit <- do_group_exit <- [unknown]
  6.496172 [003] gnome-terminal-[4391] 0.000  0.003  0.076 __schedule <- schedule <- schedule_hrtimeout_range_clock <- schedule_hrtimeo

After:

  [root@jouet experimental]# perf sched timehist
      time  cpu  task name         wait time sch delay run time
                 [tid/pid]            (msec)  (msec)  (msec)
  ----------- -----  ----------------- -----  -----  ------
  6.494998 [001] <idle>                0.000  0.000  0.000
  6.495027 [002] perf[519]             0.000  0.000  0.000 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_t
  6.495096 [003] <idle>                0.000  0.000  0.000
  6.495100 [003] rcuos/0[9]            0.000  0.005  0.003 rcu_nocb_kthread <- kthread <- ret_from_fork
  6.495113 [001] perf[520]             0.000  0.008  0.114 preempt_schedule_common <- _cond_resched <- wait_for_completion <- stop_one_c
  6.495121 [000] <idle>                0.000  0.000  0.000
  6.495129 [001] migration/1[17]       0.000  0.003  0.016 smpboot_thread_fn <- kthread <- ret_from_fork
  6.496085 [002] <idle>                0.000  0.000  1.057
  6.496096 [002] kworker/u16:1[31169]  0.000  0.004  0.011 worker_thread <- kthread <- ret_from_fork
  6.496096 [003] <idle>                0.003  0.000  0.996
  6.496169 [002] <idle>                0.011  0.000  0.072
  6.496171 [000] ls[520]               0.008  0.000  1.049 do_exit <- do_group_exit <- [unknown]
  6.496172 [003] gnome-terminal-[4391] 0.000  0.003  0.076 schedule_hrtimeout_range_clock <- schedule_hrtimeout_range <- poll_schedule_
  [root@jouet experimental]#
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161124011114.7102-1-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

For tracepoint events, callchains always contain certain functions.
Sometimes it'd be better to skip those functions as they have no value.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161124011114.7102-2-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Support the PowerPC architecture using the ins_ops association
method.

Committer notes:

Testing it with a perf.data file collected on a PowerPC machine and
cross-annotated on a x86_64 workstation, using the associated vmlinux
file:

$ perf report -i perf.data.f22vm.powerdev --vmlinux vmlinux.powerpc
  .ktime_get  vmlinux.powerpc
        │      clrldi r9,r28,63
   8.57 │   ┌──bne    e0                   <- TUI cursor positioned here
        │54:│  lwsync
   2.86 │   │  std    r2,40(r1)
        │   │  ld     r9,144(r31)
        │   │  ld     r3,136(r31)
        │   │  ld     r30,184(r31)
        │   │  ld     r10,0(r9)
        │   │  mtctr  r10
        │   │  ld     r2,8(r9)
   8.57 │   │→ bctrl
        │   │  ld     r2,40(r1)
        │   │  ld     r10,160(r31)
        │   │  ld     r5,152(r31)
        │   │  lwz    r7,168(r31)
        │   │  ld     r9,176(r31)
   8.57 │   │  lwz    r6,172(r31)
        │   │  lwsync
   2.86 │   │  lwz    r8,128(r31)
        │   │  cmpw   cr7,r8,r28
   2.86 │   │↑ bne    48
        │   │  subf   r10,r10,r3
        │   │  mr     r3,r29
        │   │  and    r10,r10,r5
   2.86 │   │  mulld  r10,r10,r7
        │   │  add    r9,r10,r9
        │   │  srd    r9,r9,r6
        │   │  add    r9,r9,r30
        │   │  std    r9,0(r29)
        │   │  addi   r1,r1,144
        │   │  ld     r0,16(r1)
        │   │  ld     r28,-32(r1)
        │   │  ld     r29,-24(r1)
        │   │  ld     r30,-16(r1)
        │   │  mtlr   r0
        │   │  ld     r31,-8(r1)
        │   │← blr
   5.71 │e0:└─→mr     r1,r1
  11.43 │      mr     r2,r2
  11.43 │      lwz    r28,128(r31)
  Press 'h' for help on key bindings

  $ perf report -i perf.data.f22vm.powerdev --header-only
  # ========
  # captured on: Thu Nov 24 12:40:38 2016
  # hostname : pdev-f22-qemu
  # os release : 4.4.10-200.fc22.ppc64
  # perf version : 4.9.rc1.g6298ce
  # arch : ppc64
  # nrcpus online : 48
  # nrcpus avail : 48
  # cpudesc : POWER7 (architected), altivec supported
  # cpuid : 74,513
  # total memory : 4158976 kB
  # cmdline : /home/ravi/Workspace/linux/tools/perf/perf record -a
  # event : name = cycles:ppp, , size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|CPU|PERIOD, disabled = 1, inherit = 1, mmap = 1, comm = 1, freq = 1, task = 1, precise_ip = 3, sample_id_all = 1, exclude_guest = 1, mmap2 = 1, comm_exec = 1
  # HEADER_CPU_TOPOLOGY info available, use -I to display
  # HEADER_NUMA_TOPOLOGY info available, use -I to display
  # pmu mappings: cpu = 4, software = 1, tracepoint = 2, breakpoint = 5
  # missing features: HEADER_TRACING_DATA HEADER_BRANCH_STACK HEADER_GROUP_DESC HEADER_AUXTRACE HEADER_STAT HEADER_CACHE
  # ========
  #
  $
Signed-off-by: NRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Link: http://lkml.kernel.org/n/tip-tbjnp40ddoxxl474uvhwi6g4@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

By using arch->init() to set up some regular expressions to associate
ins_ops to ARM instructions, ditching that old table that has
instructions not present on ARM.

Take advantage of having an arch->init() to hide more arm specific stuff
from the common code, like the objdump details.

The regular expressions comes from a patch written by Kim Phillips.
Reviewed-by: NRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-77m7lufz9ajjimkrebtg5ead@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Arches like ARM will want to use regular expressions when deciding what
instructions to associate with what ins_ops, provide infrastructure for
that.
Reviewed-by: NRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-7dmnk9el2ipu3nxog092k9z5@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Some arches may want to dynamically populate the table using regular
expressions on the instruction names to associate them with a set of
parsing/formatting/etc functions (struct ins_ops), so provide a fallback
for when the ins__find() method fails.

That fall back will be able to resize the arch->instructions, setting
arch->nr_instructions appropriately, helper functions to associate an
ins_ops to an instruction name, growing the arch->instructions if needed
and resorting it are provided, all the arch specific callback needs to
do is to decide if the missing instruction should be added to
arch->instructions with a ins_ops association.
Reviewed-by: NRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-auu13yradxf7g5dgtpnzt97a@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The disasm_line::name field is always equal to ins::name, being used
just to locate the instruction's ins_ops from the per-arch instructions
table.

Eliminate this duplication, nuking that field and instead make
ins__find() return an ins_ops, store it in disasm_line::ins.ops, and
keep just in disasm_line::ins.name what was in disasm_line::name, this
way we end up not keeping a reference to entries in the per-arch
instructions table.

This in turn will help supporting multiple ways to manage the per-arch
instructions table, allowing resorting that array, for instance, when
the entries will move after references to its addresses were made. The
same problem is avoided when one grows the array with realloc.

So architectures simply keeping a constant array will work as well as
architectures building the table using regular expressions or other
logic that involves resorting the table.
Reviewed-by: NRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Riyder <chris.ryder@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-vr899azvabnw9gtuepuqfd9t@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'perf-core-for-mingo-20161123' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

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

New tool:

- 'perf sched timehist' provides an analysis of scheduling events.

  Example usage:
      perf sched record -- sleep 1
      perf sched timehist

  By default it shows the individual schedule events, including the wait
  time (time between sched-out and next sched-in events for the task), the
  task scheduling delay (time between wakeup and actually running) and run
  time for the task:

        time    cpu  task name         wait time  sch delay  run time
                     [tid/pid]            (msec)     (msec)    (msec)
    -------- ------  ----------------  ---------  ---------  --------
    1.874569 [0011]  gcc[31949]            0.014      0.000     1.148
    1.874591 [0010]  gcc[31951]            0.000      0.000     0.024
    1.874603 [0010]  migration/10[59]      3.350      0.004     0.011
    1.874604 [0011]  <idle>                1.148      0.000     0.035
    1.874723 [0005]  <idle>                0.016      0.000     1.383
    1.874746 [0005]  gcc[31949]            0.153      0.078     0.022
  ...

  Times are in msec.usec. (David Ahern, Namhyung Kim)

Improvements:

- Make 'perf c2c report' support -f/--force, to allow skipping the
  ownership check for root users, for instance, just like the other
  tools (Jiri Olsa)

- Allow sorting cachelines by total number of HITMs, in addition to
  local and remote numbers (Jiri Olsa)

Fixes:

- Make sure errors aren't suppressed by the TUI reset at the end of
  a 'perf c2c report' session (Jiri Olsa)

Infrastructure changes:

- Initial work on having the annotate code better support multiple
  architectures, including the ability to cross-annotate, i.e. to
  annotate perf.data files collected on an ARM system on a x86_64
  workstation (Arnaldo Carvalho de Melo, Ravi Bangoria, Kim Phillips)

- Use USECS_PER_SEC instead of hard coded number in libtraceevent (Steven Rostedt)

- Add retrieval of preempt count and latency flags in libtraceevent (Steven Rostedt)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Pull NFS client bugfixes from Anna Schumaker:
 "Most of these fix regressions or races, but there is one patch for
  stable that Arnd sent me

  Stable bugfix:
   - Hide array-bounds warning

  Bugfixes:
   - Keep a reference on lock states while checking
   - Handle NFS4ERR_OLD_STATEID in nfs4_reclaim_open_state
   - Don't call close if the open stateid has already been cleared
   - Fix CLOSE rases with OPEN
   - Fix a regression in DELEGRETURN"

* tag 'nfs-for-4.9-4' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFSv4.x: hide array-bounds warning
  NFSv4.1: Keep a reference on lock states while checking
  NFSv4.1: Handle NFS4ERR_OLD_STATEID in nfs4_reclaim_open_state
  NFSv4: Don't call close if the open stateid has already been cleared
  NFSv4: Fix CLOSE races with OPEN
  NFSv4.1: Fix a regression in DELEGRETURN

Pull arch/tile bugfix from Chris Metcalf:
 "This fixes a bug that causes reboots after 208 days of uptime :-)"

* 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: avoid using clocksource_cyc2ns with absolute cycle count

For large values of "mult" and long uptimes, the intermediate
result of "cycles * mult" can overflow 64 bits.  For example,
the tile platform calls clocksource_cyc2ns with a 1.2 GHz clock;
we have mult = 853, and after 208.5 days, we overflow 64 bits.

Since clocksource_cyc2ns() is intended to be used for relative
cycle counts, not absolute cycle counts, performance is more
importance than accepting a wider range of cycle values.  So,
just use mult_frac() directly in tile's sched_clock().

Commit 4cecf6d4 ("sched, x86: Avoid unnecessary overflow
in sched_clock") by Salman Qazi results in essentially the same
generated code for x86 as this change does for tile.  In fact,
a follow-on change by Salman introduced mult_frac() and switched
to using it, so the C code was largely identical at that point too.

Peter Zijlstra then added mul_u64_u32_shr() and switched x86
to use it.  This is, in principle, better; by optimizing the
64x64->64 multiplies to be 32x32->64 multiplies we can potentially
save some time.  However, the compiler piplines the 64x64->64
multiplies pretty well, and the conditional branch in the generic
mul_u64_u32_shr() causes some bubbles in execution, with the
result that it's pretty much a wash.  If tilegx provided its own
implementation of mul_u64_u32_shr() without the conditional branch,
we could potentially save 3 cycles, but that seems like small gain
for a fair amount of additional build scaffolding; no other platform
currently provides a mul_u64_u32_shr() override, and tile doesn't
currently have an <asm/div64.h> header to put the override in.

Additionally, gcc currently has an optimization bug that prevents
it from recognizing the opportunity to use a 32x32->64 multiply,
and so the result would be no better than the existing mult_frac()
until such time as the compiler is fixed.

For now, just using mult_frac() seems like the right answer.

Cc: stable@kernel.org [v3.4+]
Signed-off-by: NChris Metcalf <cmetcalf@mellanox.com>

Pull perf fixes from Ingo Molnar:
 "Six fixes for bugs that were found via fuzzing, and a trivial
  hw-enablement patch for AMD Family-17h CPU PMUs"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Allow only a single PMU/box within an events group
  perf/x86/intel: Cure bogus unwind from PEBS entries
  perf/x86: Restore TASK_SIZE check on frame pointer
  perf/core: Fix address filter parser
  perf/x86: Add perf support for AMD family-17h processors
  perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client uncore IMC
  perf/core: Do not set cpuctx->cgrp for unscheduled cgroups

The -V option provides a visual aid for sched switches by cpu:

  $ perf sched timehist -V
             time    cpu  0123456789abc  task name              b/n time  sch delay   run time
                                         [tid/pid]                (msec)     (msec)     (msec)
  --------------- ------  -------------  --------------------  ---------  ---------  ---------
  ...
   2412598.429696 [0009]           i     <idle>                    0.000      0.000      0.000
   2412598.429767 [0002]    s            perf[7219]                0.000      0.000      0.000
   2412598.429783 [0009]           s     perf[7220]                0.000      0.006      0.087
   2412598.429794 [0010]            i    <idle>                    0.000      0.000      0.000
   2412598.429795 [0009]           s     migration/9[53]           0.000      0.003      0.011
   2412598.430370 [0010]            s    sleep[7220]               0.011      0.000      0.576
   2412598.432584 [0003]     i           <idle>                    0.000      0.000      0.000
  ...

Committer notes:

'i' marks idle time, 's' are scheduler events.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-8-namhyung@kernel.org
[ Add documentation based on above commit message ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

If callchains were recorded they are appended to the line with a default stack depth of 5:

  1.874569 [0011] gcc[31949]       0.014 0.000 1.148 wait_for_completion_killable <- do_fork <- sys_vfork <- stub_vfork <- __vfork
  1.874591 [0010] gcc[31951]       0.000 0.000 0.024 __cond_resched <- _cond_resched <- wait_for_completion <- stop_one_cpu <- sched_exec
  1.874603 [0010] migration/10[59] 3.350 0.004 0.011 smpboot_thread_fn <- kthread <- ret_from_fork
  1.874604 [0011] <idle>           1.148 0.000 0.035 cpu_startup_entry <- start_secondary
  1.874723 [0005] <idle>           0.016 0.000 1.383 cpu_startup_entry <- start_secondary
  1.874746 [0005] gcc[31949]       0.153 0.078 0.022 do_wait sys_wait4 <- system_call_fastpath <- __GI___waitpid

 --no-call-graph can be used to not show the callchains. --max-stack is used
to control the number of frames shown (default of 5). -x/--excl options can
be used to collapse redundant callchains to get more relevant data on screen.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-7-namhyung@kernel.org
[ Add documentation based on above commit message ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The -w option is to show wakeup events with timehist.

  $ perf sched timehist -w
             time    cpu  task name              b/n time  sch delay   run time
                          [tid/pid]                (msec)     (msec)     (msec)
  --------------- ------  --------------------  ---------  ---------  ---------
   2412598.429689 [0002]  perf[7219]                                             awakened: perf[7220]
   2412598.429696 [0009]  <idle>                    0.000      0.000      0.000
   2412598.429767 [0002]  perf[7219]                0.000      0.000      0.000
   2412598.429780 [0009]  perf[7220]                                             awakened: migration/9[53]
  ...
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-6-namhyung@kernel.org
[ Add documentation based on above commit message ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The -s/--summary option is to show process runtime statistics.  And the
 -S/--with-summary option is to show the stats with the normal output.

  $ perf sched timehist -s

  Runtime summary
                            comm  parent   sched-in     run-time    min-run     avg-run     max-run  stddev
                                            (count)       (msec)     (msec)      (msec)      (msec)       %
  ---------------------------------------------------------------------------------------------------------
                  ksoftirqd/0[3]       2          2        0.011      0.004       0.005       0.006   14.87
                  rcu_preempt[7]       2         11        0.071      0.002       0.006       0.017   20.23
                  watchdog/0[11]       2          1        0.002      0.002       0.002       0.002    0.00
                  watchdog/1[12]       2          1        0.004      0.004       0.004       0.004    0.00
  ...

  Terminated tasks:
                     sleep[7220]    7219          3        0.770      0.087       0.256       0.576   62.28

  Idle stats:
      CPU  0 idle for   2352.006  msec
      CPU  1 idle for   2764.497  msec
      CPU  2 idle for   2998.229  msec
      CPU  3 idle for   2967.800  msec

      Total number of unique tasks: 52
  Total number of context switches: 2532
             Total run time (msec): 218.036
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-5-namhyung@kernel.org
[ Add documentation from last commit, so that docs comes with the cset that introduces the feature ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

'perf sched timehist' provides an analysis of scheduling events.

Example usage:
    perf sched record -- sleep 1
    perf sched timehist

By default it shows the individual schedule events, including the wait
time (time between sched-out and next sched-in events for the task), the
task scheduling delay (time between wakeup and actually running) and run
time for the task:

            time    cpu  task name             wait time  sch delay   run time
                         [tid/pid]                (msec)     (msec)     (msec)
  -------------- ------  --------------------  ---------  ---------  ---------
    79371.874569 [0011]  gcc[31949]                0.014      0.000      1.148
    79371.874591 [0010]  gcc[31951]                0.000      0.000      0.024
    79371.874603 [0010]  migration/10[59]          3.350      0.004      0.011
    79371.874604 [0011]  <idle>                    1.148      0.000      0.035
    79371.874723 [0005]  <idle>                    0.016      0.000      1.383
    79371.874746 [0005]  gcc[31949]                0.153      0.078      0.022
...

Times are in msec.usec.

Committer note:

Add above explanation as the 'perf sched timehist' entry for 'man
perf-sched'.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-4-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The EVSEL__PRINT_CALLCHAIN_ARROW options can be used to print callchains
with arrows for readability.  It will be used 'sched timehist' command
like below:

    __schedule <- schedule <- schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
    __schedule <- schedule <- schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
    __schedule <- schedule <- worker_thread <- kthread <- ret_from_fork
Suggested-and-Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-3-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The __symbol__fprintf_symname_offs() always shows symbol offsets.  So
there's no difference between 'perf script -F ip,sym' and 'perf script
-F ip,sym,symoff'.  I don't think it's a desired behavior..
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20161116060634.28477-2-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Adding support for cascading options added by Namhyung in:

  commit 369a2478 ("tools lib subcmd: Support cascading options")

This way the report and record command share options with with c2c
command and can save some option duplicates. For now it's the 'v'
option.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-7-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Currently we display the cacheline list sorted on remote HITMs by
default.

The problem is that they might not be always counted and 'perf c2c
report' displays an empty output. Thus it's more convenient to display
and sort the cacheline list based on the total of HITMs and have the
best change to see data in the default report run.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-6-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Count total number of HITMs in a special field. This will ease up
addition of total HITM sorting into c2c report in the following patch.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-5-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Adding -f/--force option to go through ownership validation:

  $ sudo perf c2c report
  File perf.data not owned by current user or root (use -f to override)
  $
  $ sudo perf c2c report -f
  < c2c report output >
  $
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-4-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Because of the early browser switch we won't get possible error
messages, as it will clear the screen right after showing the message,
e.g.:

Before:

   $ sudo perf c2c report -d lcl
   $

After:
   $ sudo perf c2c report -d lcl
   File perf.data not owned by current user or root (use -f to override)
   $
   $ ls -la perf.data
   -rw-------. 1 acme acme 26648 Nov 22 15:11 perf.data
   $
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-3-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

It is useful for debug to see file descriptors for each event.

Before:

  $ perf stat -vvv -e cycles,cache-misses ls
  ...
  sys_perf_event_open: pid 12146  cpu -1  group_fd -1  flags 0x8
  ...
  sys_perf_event_open: pid 12146  cpu -1  group_fd 3  flags 0x8
  sys_perf_event_open failed, error -13

Now:

  $ perf stat -vvv -e cycles,cache-misses ls
  ...
  sys_perf_event_open: pid 12858  cpu -1  group_fd -1  flags 0x8 = 3
  ...
  sys_perf_event_open: pid 12858  cpu -1  group_fd 3  flags 0x8
  sys_perf_event_open failed, error -13
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1479764011-10732-2-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Add a way to retrieve the preempt count as well as the latency flags from a
pevent_record.

  int pevent_data_preempt_count(pevent, record);

returns the preempt count of a record.

  int pevent_data_flags(pevent, record);

returns the latency flags for a record.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20161122113158.03a010a8@gandalf.local.homeSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Instead of using 1000000, use the define in time64.h instead.

Also remove the the duplicate defines for NSECS_PER_SEC.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20161121114149.67111981@gandalf.local.homeSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Pull crypto fixes from Herbert Xu:
 "The last push broke algif_hash for all shash implementations, so this
  is a follow-up to fix that.

  This also fixes a problem in the crypto scatterwalk that triggers a
  BUG_ON with certain debugging options due to the new vmalloced-stack
  code"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: scatterwalk - Remove unnecessary aliasing check in map_and_copy
  crypto: algif_hash - Fix result clobbering in recvmsg

Pull thermal management fix from Zhang Rui:
 "We only have one urgent fix this time.

  Commit 3105f234 ("thermal/powerclamp: correct cpu support check"),
  which is shipped in 4.9-rc3, fixed a problem introduced by commit
  b721ca0d ("thermal/powerclamp: remove cpu whitelist").

  But unfortunately, it broke intel_powerclamp driver module auto-
  loading at the same time. Thus we need this change to add back module
  auto-loading for 4.9"

* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
  thermal/powerclamp: add back module device table

Pull SCSI fixes from James Bottomley:
 "Two small fixes.

  One prevents timeouts on mpt3sas when trying to use the secure erase
  protocol which causes the erase protocol to be aborted. The second is
  a regression in a prior fix which causes all commands to abort during
  PCI extended error recovery, which is incorrect because PCI EEH is
  independent from what's happening on the FC transport"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qla2xxx: do not abort all commands in the adapter during EEH recovery
  scsi: mpt3sas: Fix secure erase premature termination

Pull clk fixes from Stephen Boyd:
 "A handful of driver fixes.

  The sunxi fixes are for an incorrect clk tree configuration and a bad
  frequency calculation. The other two are fixes for passing the wrong
  pointer in drivers recently converted to clk_hw style registration"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: efm32gg: Pass correct type to hw provider registration
  clk: berlin: Pass correct type to hw provider registration
  clk: sunxi: Fix M factor computation for APB1
  clk: sunxi-ng: sun6i-a31: Force AHB1 clock to use PLL6 as parent

A correct bugfix introduced a harmless warning that shows up with gcc-7:

fs/nfs/callback.c: In function 'nfs_callback_up':
fs/nfs/callback.c:214:14: error: array subscript is outside array bounds [-Werror=array-bounds]

What happens here is that the 'minorversion == 0' check tells the
compiler that we assume minorversion can be something other than 0,
but when CONFIG_NFS_V4_1 is disabled that would be invalid and
result in an out-of-bounds access.

The added check for IS_ENABLED(CONFIG_NFS_V4_1) tells gcc that this
really can't happen, which makes the code slightly smaller and also
avoids the warning.

The bugfix that introduced the warning is marked for stable backports,
we want this one backported to the same releases.

Fixes: 98b0f80c ("NFSv4.x: Fix a refcount leak in nfs_callback_up_net")
Cc: stable@vger.kernel.org # v3.7+
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Pull scheduler fixes from Ingo Molnar:
 "Two fixes for autogroup scheduling, for races when turning the feature
  on/off via /proc/sys/kernel/sched_autogroup_enabled"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/autogroup: Do not use autogroup->tg in zombie threads
  sched/autogroup: Fix autogroup_move_group() to never skip sched_move_task()

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:
   - two fixes to make (very) old Intel CPUs boot reliably
   - fix the intel-mid driver and rename it
   - two KASAN false positive fixes
   - an FPU fix
   - two sysfb fixes
   - two build fixes related to new toolchain versions"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt
  x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well
  x86/platform/intel-mid: Register watchdog device after SCU
  x86/fpu: Fix invalid FPU ptrace state after execve()
  x86/boot: Fail the boot if !M486 and CPUID is missing
  x86/traps: Ignore high word of regs->cs in early_fixup_exception()
  x86/dumpstack: Prevent KASAN false positive warnings
  x86/unwind: Prevent KASAN false positive warnings in guess unwinder
  x86/boot: Avoid warning for zero-filling .bss
  x86/sysfb: Fix lfb_size calculation
  x86/sysfb: Add support for 64bit EFI lfb_base

Group validation expects all events to be of the same PMU; however
is_uncore_pmu() is too wide, it matches _all_ uncore events, even
across PMUs.

This triggers failure when we group different events from different
uncore PMUs, like:

  perf stat -vv -e '{uncore_cbox_0/config=0x0334/,uncore_qpi_0/event=1/}' -a sleep 1

Fix is_uncore_pmu() by only matching events to the box at hand.

Note that generic code; ran after this step; will disallow this
mixture of PMU events.
Reported-by: NJiri Olsa <jolsa@redhat.com>
Tested-by: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20161118125354.GQ3117@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Vince Weaver reported that perf_fuzzer + KASAN detects that PEBS event
unwinds sometimes do 'weird' things. In particular, we seemed to be
ending up unwinding from random places on the NMI stack.

While it was somewhat expected that the event record BP,SP would not
match the interrupt BP,SP in that the interrupt is strictly later than
the record event, it was overlooked that it could be on an already
overwritten stack.

Therefore, don't copy the recorded BP,SP over the interrupted BP,SP
when we need stack unwinds.

Note that its still possible the unwind doesn't full match the actual
event, as its entirely possible to have done an (I)RET between record
and interrupt, but on average it should still point in the general
direction of where the event came from. Also, it's the best we can do,
considering.

The particular scenario that triggered the bogus NMI stack unwind was
a PEBS event with very short period, upon enabling the event at the
tail of the PMI handler (FREEZE_ON_PMI is not used), it instantly
triggers a record (while still on the NMI stack) which in turn
triggers the next PMI. This then causes back-to-back NMIs and we'll
try and unwind the stack-frame from the last NMI, which obviously is
now overwritten by our own.
Analyzed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davej@codemonkey.org.uk <davej@codemonkey.org.uk>
Cc: dvyukov@google.com <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: ca037701 ("perf, x86: Add PEBS infrastructure")
Link: http://lkml.kernel.org/r/20161117171731.GV3157@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

The following commit:

  75925e1a ("perf/x86: Optimize stack walk user accesses")

... switched from copy_from_user_nmi() to __copy_from_user_nmi() with a manual
access_ok() check.

Unfortunately, copy_from_user_nmi() does an explicit check against TASK_SIZE,
whereas the access_ok() uses whatever the current address limit of the task is.

We are getting NMIs when __probe_kernel_read() has switched to KERNEL_DS, and
then see vmalloc faults when we access what looks like pointers into vmalloc
space:

  [] WARNING: CPU: 3 PID: 3685731 at arch/x86/mm/fault.c:435 vmalloc_fault+0x289/0x290
  [] CPU: 3 PID: 3685731 Comm: sh Tainted: G        W       4.6.0-5_fbk1_223_gdbf0f40 #1
  [] Call Trace:
  []  <NMI>  [<ffffffff814717d1>] dump_stack+0x4d/0x6c
  []  [<ffffffff81076e43>] __warn+0xd3/0xf0
  []  [<ffffffff81076f2d>] warn_slowpath_null+0x1d/0x20
  []  [<ffffffff8104a899>] vmalloc_fault+0x289/0x290
  []  [<ffffffff8104b5a0>] __do_page_fault+0x330/0x490
  []  [<ffffffff8104b70c>] do_page_fault+0xc/0x10
  []  [<ffffffff81794e82>] page_fault+0x22/0x30
  []  [<ffffffff81006280>] ? perf_callchain_user+0x100/0x2a0
  []  [<ffffffff8115124f>] get_perf_callchain+0x17f/0x190
  []  [<ffffffff811512c7>] perf_callchain+0x67/0x80
  []  [<ffffffff8114e750>] perf_prepare_sample+0x2a0/0x370
  []  [<ffffffff8114e840>] perf_event_output+0x20/0x60
  []  [<ffffffff8114aee7>] ? perf_event_update_userpage+0xc7/0x130
  []  [<ffffffff8114ea01>] __perf_event_overflow+0x181/0x1d0
  []  [<ffffffff8114f484>] perf_event_overflow+0x14/0x20
  []  [<ffffffff8100a6e3>] intel_pmu_handle_irq+0x1d3/0x490
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff81197191>] ? vunmap_page_range+0x1a1/0x2f0
  []  [<ffffffff811972f1>] ? unmap_kernel_range_noflush+0x11/0x20
  []  [<ffffffff814f2056>] ? ghes_copy_tofrom_phys+0x116/0x1f0
  []  [<ffffffff81040d1d>] ? x2apic_send_IPI_self+0x1d/0x20
  []  [<ffffffff8100411d>] perf_event_nmi_handler+0x2d/0x50
  []  [<ffffffff8101ea31>] nmi_handle+0x61/0x110
  []  [<ffffffff8101ef94>] default_do_nmi+0x44/0x110
  []  [<ffffffff8101f13b>] do_nmi+0xdb/0x150
  []  [<ffffffff81795187>] end_repeat_nmi+0x1a/0x1e
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
  []  <<EOE>>  <IRQ>  [<ffffffff8115d05e>] ? __probe_kernel_read+0x3e/0xa0

Fix this by moving the valid_user_frame() check to before the uaccess
that loads the return address and the pointer to the next frame.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Fixes: 75925e1a ("perf/x86: Optimize stack walk user accesses")
Signed-off-by: NIngo Molnar <mingo@kernel.org>