Drew Richardson reported that he could make the kernel go *boom* when hotplugging
while having perf events active.

It turned out that when you have a group event, the code in
__perf_event_exit_context() fails to remove the group siblings from
the context.

We then proceed with destroying and freeing the event, and when you
re-plug the CPU and try and add another event to that CPU, things go
*boom* because you've still got dead entries there.

Reported-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/n/tip-k6v5wundvusvcseqj1si0oz0@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pick up the latest fixes, refresh the development tree.

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

Unlike recent modern userspace API such as:

  epoll_create1 (EPOLL_CLOEXEC), eventfd (EFD_CLOEXEC),
  fanotify_init (FAN_CLOEXEC), inotify_init1 (IN_CLOEXEC),
  signalfd (SFD_CLOEXEC), timerfd_create (TFD_CLOEXEC),
  or the venerable general purpose open (O_CLOEXEC),

perf_event_open() syscall lack a flag to atomically set FD_CLOEXEC
(eg. close-on-exec) flag on file descriptor it returns to userspace.

The present patch adds a PERF_FLAG_FD_CLOEXEC flag to allow
perf_event_open() syscall to atomically set close-on-exec.

Having this flag will enable userspace to remove the file descriptor
from the list of file descriptors being inherited across exec,
without the need to call fcntl(fd, F_SETFD, FD_CLOEXEC) and the
associated race condition between the current thread and another
thread calling fork(2) then execve(2).

Links:

 - Secure File Descriptor Handling (Ulrich Drepper, 2008)
   http://udrepper.livejournal.com/20407.html

 - Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012)
   http://danwalsh.livejournal.com/53603.html

 - Notes in DMA buffer sharing: leak and security hole
   http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/dma-buf-sharing.txt?id=v3.13-rc3#n428

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This patch fixes a problem with the initialization of the
struct perf_event active_entry field. It is defined inside
an anonymous union and was initialized in perf_event_alloc()
using INIT_LIST_HEAD(). However at that time, we do not know
whether the event is going to use active_entry or hlist_entry (SW).
Or at last, we don't want to make that determination there.
The problem is that hlist and list_head are not initialized
the same way. One is okay with NULL (from kzmalloc), the other
needs to pointers to point to self.

This patch resolves this problem by dropping the union.
This will avoid problems later on, if someone starts using
active_entry or hlist_entry without verifying that they
actually overlap. This also solves the initialization
problem.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: vincent.weaver@maine.edu
Cc: maria.n.dimakopoulou@gmail.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389176153-3128-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Vince Weaver reports that, on all architectures apart from ARM,
PERF_EVENT_IOC_PERIOD doesn't actually update the period until the next
event fires. This is counter-intuitive behaviour and is better dealt
with in the core code.

This patch ensures that the period is forcefully reset when dealing with
such a request in the core code. A subsequent patch removes the
equivalent hack from the ARM back-end.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1385560479-11014-1-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Currently, only one PMU in a context gets disabled during unthrottling
and event_sched_{out,in}(), however, events in one context may belong to
different pmus, which results in PMUs being reprogrammed while they are
still enabled.

This means that mixed PMU use [which is rare in itself] resulted in
potentially completely unreliable results: corrupted events, bogus
results, etc.

This patch temporarily disables PMUs that correspond to
each event in the context while these events are being modified.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This patch adds a new field to the struct perf_event.
It is intended to be used to chain events which are
active (enabled). It helps in the hardware layer
for PMUs which do not have actual counter restrictions, i.e.,
free running read-only counters. Active events are chained
as opposed to being tracked via the counter they use.

To save space we use a union with hlist_entry as both
are mutually exclusive (suggested by Jiri Olsa).

Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1384275531-10892-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Currently we only allocate a single cpu hashtable for per-cpu
swevents; do away with this optimization for it is fragile in the face
of things like perf_pmu_migrate_context().

The easiest thing is to make sure all CPUs are consistent wrt state.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130913111447.GN31370@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Add two trivial helpers list_next_entry() and list_prev_entry(), they
can have a lot of users including list.h itself.  In fact the 1st one is
already defined in events/core.c and bnx2x_sp.c, so the patch simply
moves the definition to list.h.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull perf updates from Ingo Molnar:
 "As a first remark I'd like to note that the way to build perf tooling
  has been simplified and sped up, in the future it should be enough for
  you to build perf via:

        cd tools/perf/
        make install

  (ie without the -j option.) The build system will figure out the
  number of CPUs and will do a parallel build+install.

  The various build system inefficiencies and breakages Linus reported
  against the v3.12 pull request should now be resolved - please
  (re-)report any remaining annoyances or bugs.

  Main changes on the perf kernel side:

   * Performance optimizations:
      . perf ring-buffer code optimizations,          by Peter Zijlstra
      . perf ring-buffer code optimizations,          by Oleg Nesterov
      . x86 NMI call-stack processing optimizations,  by Peter Zijlstra
      . perf context-switch optimizations,            by Peter Zijlstra
      . perf sampling speedups,                       by Peter Zijlstra
      . x86 Intel PEBS processing speedups,           by Peter Zijlstra

   * Enhanced hardware support:
      . for Intel Ivy Bridge-EP uncore PMUs,          by Zheng Yan
      . for Haswell transactions,                     by Andi Kleen, Peter Zijlstra

   * Core perf events code enhancements and fixes by Oleg Nesterov:
      . for uprobes, if fork() is called with pending ret-probes
      . for uprobes platform support code

   * New ABI details by Andi Kleen:
      . Report x86 Haswell TSX transaction abort cost as weight

  Main changes on the perf tooling side (some of these tooling changes
  utilize the above kernel side changes):

   * 'perf report/top' enhancements:

      . Convert callchain children list to rbtree, greatly reducing the
        time taken for callchain processing, from Namhyung Kim.

      . Add new COMM infrastructure, further improving histogram
        processing, from Frédéric Weisbecker, one fix from Namhyung Kim.

      . Add /proc/kcore based live-annotation improvements, including
        build-id cache support, multi map 'call' instruction navigation
        fixes, kcore address validation, objdump workarounds.  From
        Adrian Hunter.

      . Show progress on histogram collapsing, that can take a long
        time, from Namhyung Kim.

      . Add --max-stack option to limit callchain stack scan in 'top'
        and 'report', improving callchain processing when reducing the
        stack depth is an option, from Waiman Long.

      . Add new option --ignore-vmlinux for perf top, from Willy
        Tarreau.

   * 'perf trace' enhancements:

      . 'perf trace' now can can use a 'perf probe' dynamic tracepoints
        to hook into the userspace -> kernel pathname copy so that it
        can map fds to pathnames without reading /proc/pid/fd/ symlinks.
        From Arnaldo Carvalho de Melo.

      . Show VFS path associated with fd in live sessions, using a
        'vfs_getname' 'perf probe' created dynamic tracepoint or by
        looking at /proc/pid/fd, from Arnaldo Carvalho de Melo.

      . Add 'trace' beautifiers for lots of syscall arguments, from
        Arnaldo Carvalho de Melo.

      . Implement more compact 'trace' output by suppressing zeroed
        args, from Arnaldo Carvalho de Melo.

      . Show thread COMM by default in 'trace', from Arnaldo Carvalho de
        Melo.

      . Add option to show full timestamp in 'trace', from David Ahern.

      . Add 'record' command in 'trace', to record raw_syscalls:*, from
        David Ahern.

      . Add summary option to dump syscall statistics in 'trace', from
        David Ahern.

      . Improve error messages in 'trace', providing hints about system
        configuration steps needed for using it, from Ramkumar
        Ramachandra.

      . 'perf trace' now emits hints as to why tracing is not possible,
        helping the user to setup the system to allow tracing in the
        desired permission granularity, telling if the problem is due to
        debugfs not being mounted or with not enough permission for
        !root, /proc/sys/kernel/perf_event_paranoit value, etc.  From
        Arnaldo Carvalho de Melo.

   * 'perf record' enhancements:

      . Check maximum frequency rate for record/top, emitting better
        error messages, from Jiri Olsa.

      . 'perf record' code cleanups, from David Ahern.

      . Improve write_output error message in 'perf record', from Adrian
        Hunter.

      . Allow specifying B/K/M/G unit to the --mmap-pages arguments,
        from Jiri Olsa.

      . Fix command line callchain attribute tests to handle the new
        -g/--call-chain semantics, from Arnaldo Carvalho de Melo.

   * 'perf kvm' enhancements:

      . Disable live kvm command if timerfd is not supported, from David
        Ahern.

      . Fix detection of non-core features, from David Ahern.

   * 'perf list' enhancements:

      . Add usage to 'perf list', from David Ahern.

      . Show error in 'perf list' if tracepoints not available, from
        Pekka Enberg.

   * 'perf probe' enhancements:

      . Support "$vars" meta argument syntax for local variables,
        allowing asking for all possible variables at a given probe
        point to be collected when it hits, from Masami Hiramatsu.

   * 'perf sched' enhancements:

      . Address the root cause of that 'perf sched' stack initialization
        build slowdown, by programmatically setting a big array after
        moving the global variable back to the stack.  Fix from Adrian
        Hunter.

   * 'perf script' enhancements:

      . Set up output options for in-stream attributes, from Adrian
        Hunter.

      . Print addr by default for BTS in 'perf script', from Adrian
        Juntmer

   * 'perf stat' enhancements:

      . Improved messages when doing profiling in all or a subset of
        CPUs using a workload as the session delimitator, as in:

         'perf stat --cpu 0,2 sleep 10s'

        from Arnaldo Carvalho de Melo.

      . Add units to nanosec-based counters in 'perf stat', from David
        Ahern.

      . Remove bogus info when using 'perf stat' -e cycles/instructions,
        from Ramkumar Ramachandra.

   * 'perf lock' enhancements:

      . 'perf lock' fixes and cleanups, from Davidlohr Bueso.

   * 'perf test' enhancements:

      . Fixup PERF_SAMPLE_TRANSACTION handling in sample synthesizing
        and 'perf test', from Adrian Hunter.

      . Clarify the "sample parsing" test entry, from Arnaldo Carvalho
        de Melo.

      . Consider PERF_SAMPLE_TRANSACTION in the "sample parsing" test,
        from Arnaldo Carvalho de Melo.

      . Memory leak fixes in 'perf test', from Felipe Pena.

   * 'perf bench' enhancements:

      . Change the procps visible command-name of invididual benchmark
        tests plus cleanups, from Ingo Molnar.

   * Generic perf tooling infrastructure/plumbing changes:

      . Separating data file properties from session, code
        reorganization from Jiri Olsa.

      . Fix version when building out of tree, as when using one of
        these:

        $ make help | grep perf
          perf-tar-src-pkg    - Build perf-3.12.0.tar source tarball
          perf-targz-src-pkg  - Build perf-3.12.0.tar.gz source tarball
          perf-tarbz2-src-pkg - Build perf-3.12.0.tar.bz2 source tarball
          perf-tarxz-src-pkg  - Build perf-3.12.0.tar.xz source tarball
        $

        from David Ahern.

      . Enhance option parse error message, showing just the help lines
        of the options affected, from Namhyung Kim.

      . libtraceevent updates from upstream trace-cmd repo, from Steven
        Rostedt.

      . Always use perf_evsel__set_sample_bit to set sample_type, from
        Adrian Hunter.

      . Memory and mmap leak fixes from Chenggang Qin.

      . Assorted build fixes for from David Ahern and Jiri Olsa.

      . Speed up and prettify the build system, from Ingo Molnar.

      . Implement addr2line directly using libbfd, from Roberto Vitillo.

      . Separate the GTK support in a separate libperf-gtk.so DSO, that
        is only loaded when --gtk is specified, from Namhyung Kim.

      . perf bash completion fixes and improvements from Ramkumar
        Ramachandra.

      . Support for Openembedded/Yocto -dbg packages, from Ricardo
        Ribalda Delgado.

  And lots and lots of other fixes and code reorganizations that did not
  make it into the list, see the shortlog, diffstat and the Git log for
  details!"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (300 commits)
  uprobes: Fix the memory out of bound overwrite in copy_insn()
  uprobes: Fix the wrong usage of current->utask in uprobe_copy_process()
  perf tools: Remove unneeded include
  perf record: Remove post_processing_offset variable
  perf record: Remove advance_output function
  perf record: Refactor feature handling into a separate function
  perf trace: Don't relookup fields by name in each sample
  perf tools: Fix version when building out of tree
  perf evsel: Ditch evsel->handler.data field
  uprobes: Export write_opcode() as uprobe_write_opcode()
  uprobes: Introduce arch_uprobe->ixol
  uprobes: Kill module_init() and module_exit()
  uprobes: Move function declarations out of arch
  perf/x86/intel: Add Ivy Bridge-EP uncore IRP box support
  perf/x86/intel/uncore: Add filter support for IvyBridge-EP QPI boxes
  perf: Factor out strncpy() in perf_event_mmap_event()
  tools/perf: Add required memory barriers
  perf: Fix arch_perf_out_copy_user default
  perf: Update a stale comment
  perf: Optimize perf_output_begin() -- address calculation
  ...