Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 232 insertions, 0 deletions

diff --git a/Documentation/driver-api/dmaengine/dmatest.rst b/Documentation/driver-api/dmaengine/dmatest.rst
new file mode 100644
index 000000000..e2a63cefd
--- /dev/null
+++ b/Documentation/driver-api/dmaengine/dmatest.rst
@@ -0,0 +1,232 @@
+==============
+DMA Test Guide
+==============
+
+Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+
+This small document introduces how to test DMA drivers using dmatest module.
+
+The dmatest module tests DMA memcpy, memset, XOR and RAID6 P+Q operations using
+various lengths and various offsets into the source and destination buffers. It
+will initialize both buffers with a repeatable pattern and verify that the DMA
+engine copies the requested region and nothing more. It will also verify that
+the bytes aren't swapped around, and that the source buffer isn't modified.
+
+The dmatest module can be configured to test a specific channel. It can also
+test multiple channels at the same time, and it can start multiple threads
+competing for the same channel.
+
+.. note::
+  The test suite works only on the channels that have at least one
+  capability of the following: DMA_MEMCPY (memory-to-memory), DMA_MEMSET
+  (const-to-memory or memory-to-memory, when emulated), DMA_XOR, DMA_PQ.
+
+.. note::
+  In case of any related questions use the official mailing list
+  dmaengine@vger.kernel.org.
+
+Part 1 - How to build the test module
+=====================================
+
+The menuconfig contains an option that could be found by following path:
+
+	Device Drivers -> DMA Engine support -> DMA Test client
+
+In the configuration file the option called CONFIG_DMATEST. The dmatest could
+be built as module or inside kernel. Let's consider those cases.
+
+Part 2 - When dmatest is built as a module
+==========================================
+
+Example of usage::
+
+    % modprobe dmatest timeout=2000 iterations=1 channel=dma0chan0 run=1
+
+...or::
+
+    % modprobe dmatest
+    % echo 2000 > /sys/module/dmatest/parameters/timeout
+    % echo 1 > /sys/module/dmatest/parameters/iterations
+    % echo dma0chan0 > /sys/module/dmatest/parameters/channel
+    % echo 1 > /sys/module/dmatest/parameters/run
+
+...or on the kernel command line::
+
+    dmatest.timeout=2000 dmatest.iterations=1 dmatest.channel=dma0chan0 dmatest.run=1
+
+Example of multi-channel test usage (new in the 5.0 kernel)::
+
+    % modprobe dmatest
+    % echo 2000 > /sys/module/dmatest/parameters/timeout
+    % echo 1 > /sys/module/dmatest/parameters/iterations
+    % echo dma0chan0 > /sys/module/dmatest/parameters/channel
+    % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+    % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+    % echo 1 > /sys/module/dmatest/parameters/run
+
+.. note::
+  For all tests, starting in the 5.0 kernel, either single- or multi-channel,
+  the channel parameter(s) must be set after all other parameters. It is at
+  that time that the existing parameter values are acquired for use by the
+  thread(s). All other parameters are shared. Therefore, if changes are made
+  to any of the other parameters, and an additional channel specified, the
+  (shared) parameters used for all threads will use the new values.
+  After the channels are specified, each thread is set as pending. All threads
+  begin execution when the run parameter is set to 1.
+
+.. hint::
+  A list of available channels can be found by running the following command::
+
+    % ls -1 /sys/class/dma/
+
+Once started a message like " dmatest: Added 1 threads using dma0chan0" is
+emitted. A thread for that specific channel is created and is now pending, the
+pending thread is started once run is to 1.
+
+Note that running a new test will not stop any in progress test.
+
+The following command returns the state of the test. ::
+
+    % cat /sys/module/dmatest/parameters/run
+
+To wait for test completion userspace can poll 'run' until it is false, or use
+the wait parameter. Specifying 'wait=1' when loading the module causes module
+initialization to pause until a test run has completed, while reading
+/sys/module/dmatest/parameters/wait waits for any running test to complete
+before returning. For example, the following scripts wait for 42 tests
+to complete before exiting. Note that if 'iterations' is set to 'infinite' then
+waiting is disabled.
+
+Example::
+
+    % modprobe dmatest run=1 iterations=42 wait=1
+    % modprobe -r dmatest
+
+...or::
+
+    % modprobe dmatest run=1 iterations=42
+    % cat /sys/module/dmatest/parameters/wait
+    % modprobe -r dmatest
+
+Part 3 - When built-in in the kernel
+====================================
+
+The module parameters that is supplied to the kernel command line will be used
+for the first performed test. After user gets a control, the test could be
+re-run with the same or different parameters. For the details see the above
+section `Part 2 - When dmatest is built as a module`_.
+
+In both cases the module parameters are used as the actual values for the test
+case. You always could check them at run-time by running ::
+
+    % grep -H . /sys/module/dmatest/parameters/*
+
+Part 4 - Gathering the test results
+===================================
+
+Test results are printed to the kernel log buffer with the format::
+
+    "dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
+
+Example of output::
+
+    % dmesg | tail -n 1
+    dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
+
+The message format is unified across the different types of errors. A
+number in the parentheses represents additional information, e.g. error
+code, error counter, or status. A test thread also emits a summary line at
+completion listing the number of tests executed, number that failed, and a
+result code.
+
+Example::
+
+    % dmesg | tail -n 1
+    dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
+
+The details of a data miscompare error are also emitted, but do not follow the
+above format.
+
+Part 5 - Handling channel allocation
+====================================
+
+Allocating Channels
+-------------------
+
+Channels do not need to be configured prior to starting a test run. Attempting
+to run the test without configuring the channels will result in testing any
+channels that are available.
+
+Example::
+
+    % echo 1 > /sys/module/dmatest/parameters/run
+    dmatest: No channels configured, continue with any
+
+Channels are registered using the "channel" parameter. Channels can be requested by their
+name, once requested, the channel is registered and a pending thread is added to the test list.
+
+Example::
+
+    % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+    dmatest: Added 1 threads using dma0chan2
+
+More channels can be added by repeating the example above.
+Reading back the channel parameter will return the name of last channel that was added successfully.
+
+Example::
+
+    % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+    dmatest: Added 1 threads using dma0chan1
+    % echo dma0chan2 > /sys/module/dmatest/parameters/channel
+    dmatest: Added 1 threads using dma0chan2
+    % cat /sys/module/dmatest/parameters/channel
+    dma0chan2
+
+Another method of requesting channels is to request a channel with an empty string, Doing so
+will request all channels available to be tested:
+
+Example::
+
+    % echo "" > /sys/module/dmatest/parameters/channel
+    dmatest: Added 1 threads using dma0chan0
+    dmatest: Added 1 threads using dma0chan3
+    dmatest: Added 1 threads using dma0chan4
+    dmatest: Added 1 threads using dma0chan5
+    dmatest: Added 1 threads using dma0chan6
+    dmatest: Added 1 threads using dma0chan7
+    dmatest: Added 1 threads using dma0chan8
+
+At any point during the test configuration, reading the "test_list" parameter will
+print the list of currently pending tests.
+
+Example::
+
+    % cat /sys/module/dmatest/parameters/test_list
+    dmatest: 1 threads using dma0chan0
+    dmatest: 1 threads using dma0chan3
+    dmatest: 1 threads using dma0chan4
+    dmatest: 1 threads using dma0chan5
+    dmatest: 1 threads using dma0chan6
+    dmatest: 1 threads using dma0chan7
+    dmatest: 1 threads using dma0chan8
+
+Note: Channels will have to be configured for each test run as channel configurations do not
+carry across to the next test run.
+
+Releasing Channels
+-------------------
+
+Channels can be freed by setting run to 0.
+
+Example::
+
+    % echo dma0chan1 > /sys/module/dmatest/parameters/channel
+    dmatest: Added 1 threads using dma0chan1
+    % cat /sys/class/dma/dma0chan1/in_use
+    1
+    % echo 0 > /sys/module/dmatest/parameters/run
+    % cat /sys/class/dma/dma0chan1/in_use
+    0
+
+Channels allocated by previous test runs are automatically freed when a new
+channel is requested after completing a successful test run.