linux-stable.git/kernel/events, branch v3.18.136

perf/core: Fix impossible ring-buffer sizes warning

2019-02-20T09:09:10+00:00

commit 528871b456026e6127d95b1b2bd8e3a003dc1614 upstream.

The following commit:

  9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")

results in perf recording failures with larger mmap areas:

  root@skl:/tmp# perf record -g -a
  failed to mmap with 12 (Cannot allocate memory)

The root cause is that the following condition is buggy:

	if (order_base_2(size) >= MAX_ORDER)
		goto fail;

The problem is that @size is in bytes and MAX_ORDER is in pages,
so the right test is:

	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
		goto fail;

Fix it.

Reported-by: "Jin, Yao" 
Bisected-by: Borislav Petkov 
Analyzed-by: Peter Zijlstra 
Cc: Julien Thierry 
Cc: Mark Rutland 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Greg Kroah-Hartman 
Cc: 
Fixes: 9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

perf/core: Don't WARN() for impossible ring-buffer sizes

2019-02-20T09:09:06+00:00

commit 9dff0aa95a324e262ffb03f425d00e4751f3294e upstream.

The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how
large its ringbuffer mmap should be. This can be configured to arbitrary
values, which can be larger than the maximum possible allocation from
kmalloc.

When this is configured to a suitably large value (e.g. thanks to the
perf fuzzer), attempting to use perf record triggers a WARN_ON_ONCE() in
__alloc_pages_nodemask():

   WARNING: CPU: 2 PID: 5666 at mm/page_alloc.c:4511 __alloc_pages_nodemask+0x3f8/0xbc8

Let's avoid this by checking that the requested allocation is possible
before calling kzalloc.

Reported-by: Julien Thierry 
Signed-off-by: Mark Rutland 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Julien Thierry 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: 
Link: https://lkml.kernel.org/r/20190110142745.25495-1-mark.rutland@arm.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

uprobes: Fix handle_swbp() vs. unregister() + register() race once more

2018-12-13T08:22:29+00:00

commit 09d3f015d1e1b4fee7e9bbdcf54201d239393391 upstream.

Commit:

  142b18ddc8143 ("uprobes: Fix handle_swbp() vs unregister() + register() race")

added the UPROBE_COPY_INSN flag, and corresponding smp_wmb() and smp_rmb()
memory barriers, to ensure that handle_swbp() uses fully-initialized
uprobes only.

However, the smp_rmb() is mis-placed: this barrier should be placed
after handle_swbp() has tested for the flag, thus guaranteeing that
(program-order) subsequent loads from the uprobe can see the initial
stores performed by prepare_uprobe().

Move the smp_rmb() accordingly.  Also amend the comments associated
to the two memory barriers to indicate their actual locations.

Signed-off-by: Andrea Parri 
Acked-by: Oleg Nesterov 
Cc: Alexander Shishkin 
Cc: Andrew Morton 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Cc: stable@kernel.org
Fixes: 142b18ddc8143 ("uprobes: Fix handle_swbp() vs unregister() + register() race")
Link: http://lkml.kernel.org/r/20181122161031.15179-1-andrea.parri@amarulasolutions.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

perf: Fix PERF_EVENT_IOC_PERIOD deadlock

2018-11-10T15:39:20+00:00

[ Upstream commit 642c2d671ceff40e9453203ea0c66e991e11e249 ]

Dmitry reported a fairly silly recursive lock deadlock for
PERF_EVENT_IOC_PERIOD, fix this by explicitly doing the inactive part of
__perf_event_period() instead of calling that function.

Reported-by: Dmitry Vyukov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: 
Cc: Alexander Potapenko 
Cc: Arnaldo Carvalho de Melo 
Cc: Arnaldo Carvalho de Melo 
Cc: Eric Dumazet 
Cc: Jiri Olsa 
Cc: Kostya Serebryany 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Sasha Levin 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Fixes: c7999c6f3fed ("perf: Fix PERF_EVENT_IOC_PERIOD migration race")
Link: http://lkml.kernel.org/r/20151130115615.GJ17308@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

perf/ring_buffer: Prevent concurent ring buffer access

2018-11-10T15:39:13+00:00

[ Upstream commit cd6fb677ce7e460c25bdd66f689734102ec7d642 ]

Some of the scheduling tracepoints allow the perf_tp_event
code to write to ring buffer under different cpu than the
code is running on.

This results in corrupted ring buffer data demonstrated in
following perf commands:

  # perf record -e 'sched:sched_switch,sched:sched_wakeup' perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  # 20 sender and receiver processes per group
  # 10 groups == 400 processes run

       Total time: 0.383 [sec]
  [ perf record: Woken up 8 times to write data ]
  0x42b890 [0]: failed to process type: -1765585640
  [ perf record: Captured and wrote 4.825 MB perf.data (29669 samples) ]

  # perf report --stdio
  0x42b890 [0]: failed to process type: -1765585640

The reason for the corruption are some of the scheduling tracepoints,
that have __perf_task dfined and thus allow to store data to another
cpu ring buffer:

  sched_waking
  sched_wakeup
  sched_wakeup_new
  sched_stat_wait
  sched_stat_sleep
  sched_stat_iowait
  sched_stat_blocked

The perf_tp_event function first store samples for current cpu
related events defined for tracepoint:

    hlist_for_each_entry_rcu(event, head, hlist_entry)
      perf_swevent_event(event, count, &data, regs);

And then iterates events of the 'task' and store the sample
for any task's event that passes tracepoint checks:

  ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);

  list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
    if (event->attr.type != PERF_TYPE_TRACEPOINT)
      continue;
    if (event->attr.config != entry->type)
      continue;

    perf_swevent_event(event, count, &data, regs);
  }

Above code can race with same code running on another cpu,
ending up with 2 cpus trying to store under the same ring
buffer, which is specifically not allowed.

This patch prevents the problem, by allowing only events with the same
current cpu to receive the event.

NOTE: this requires the use of (per-task-)per-cpu buffers for this
feature to work; perf-record does this.

Signed-off-by: Jiri Olsa 
[peterz: small edits to Changelog]
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Shishkin 
Cc: Andrew Vagin 
Cc: Arnaldo Carvalho de Melo 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Fixes: e6dab5ffab59 ("perf/trace: Add ability to set a target task for events")
Link: http://lkml.kernel.org/r/20180923161343.GB15054@krava
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

perf/core: Fix perf_output_read_group()

2018-05-30T05:47:42+00:00

[ Upstream commit 9e5b127d6f33468143d90c8a45ca12410e4c3fa7 ]

Mark reported his arm64 perf fuzzer runs sometimes splat like:

  armv8pmu_read_counter+0x1e8/0x2d8
  armpmu_event_update+0x8c/0x188
  armpmu_read+0xc/0x18
  perf_output_read+0x550/0x11e8
  perf_event_read_event+0x1d0/0x248
  perf_event_exit_task+0x468/0xbb8
  do_exit+0x690/0x1310
  do_group_exit+0xd0/0x2b0
  get_signal+0x2e8/0x17a8
  do_signal+0x144/0x4f8
  do_notify_resume+0x148/0x1e8
  work_pending+0x8/0x14

which asserts that we only call pmu::read() on ACTIVE events.

The above callchain does:

  perf_event_exit_task()
    perf_event_exit_task_context()
      task_ctx_sched_out() // INACTIVE
      perf_event_exit_event()
        perf_event_set_state(EXIT) // EXIT
        sync_child_event()
          perf_event_read_event()
            perf_output_read()
              perf_output_read_group()
                leader->pmu->read()

Which results in doing a pmu::read() on an !ACTIVE event.

I _think_ this is 'new' since we added attr.inherit_stat, which added
the perf_event_read_event() to the exit path, without that
perf_event_read_output() would only trigger from samples and for
@event to trigger a sample, it's leader _must_ be ACTIVE too.

Still, adding this check makes it consistent with the @sub case for
the siblings.

Reported-and-Tested-by: Mark Rutland 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

perf: Remove superfluous allocation error check

2018-05-16T08:05:17+00:00

commit bfb3d7b8b906b66551424d7636182126e1d134c8 upstream.

If the get_callchain_buffers fails to allocate the buffer it will
decrease the nr_callchain_events right away.

There's no point of checking the allocation error for
nr_callchain_events > 1. Removing that check.

Signed-off-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: H. Peter Anvin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: syzkaller-bugs@googlegroups.com
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20180415092352.12403-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf/core: Fix the perf_cpu_time_max_percent check

2018-05-16T08:05:14+00:00

commit 1572e45a924f254d9570093abde46430c3172e3d upstream.

Use "proc_dointvec_minmax" instead of "proc_dointvec" to check the input
value from user-space.

If not, we can set a big value and some vars will overflow like
"sysctl_perf_event_sample_rate" which will cause a lot of unexpected
problems.

Signed-off-by: Tan Xiaojun 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: 
Cc: 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Link: http://lkml.kernel.org/r/1487829879-56237-1-git-send-email-tanxiaojun@huawei.com
Signed-off-by: Ingo Molnar 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

perf: Return proper values for user stack errors

2018-04-29T05:45:27+00:00

commit 78b562fbfa2cf0a9fcb23c3154756b690f4905c1 upstream.

Return immediately when we find issue in the user stack checks. The
error value could get overwritten by following check for
PERF_SAMPLE_REGS_INTR.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: H. Peter Anvin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: syzkaller-bugs@googlegroups.com
Cc: x86@kernel.org
Fixes: 60e2364e60e8 ("perf: Add ability to sample machine state on interrupt")
Link: http://lkml.kernel.org/r/20180415092352.12403-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf/core: Correct event creation with PERF_FORMAT_GROUP

2018-04-13T17:52:19+00:00

[ Upstream commit ba5213ae6b88fb170c4771fef6553f759c7d8cdd ]

Andi was asking about PERF_FORMAT_GROUP vs inherited events, which led
to the discovery of a bug from commit:

  3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff")

 -       PERF_SAMPLE_GROUP                       = 1U << 4,
 +       PERF_SAMPLE_READ                        = 1U << 4,

 -       if (attr->inherit && (attr->sample_type & PERF_SAMPLE_GROUP))
 +       if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))

is a clear fail :/

While this changes user visible behaviour; it was previously possible
to create an inherited event with PERF_SAMPLE_READ; this is deemed
acceptible because its results were always incorrect.

Reported-by: Andi Kleen 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Fixes:  3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff")
Link: http://lkml.kernel.org/r/20170530094512.dy2nljns2uq7qa3j@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman