Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 279 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/example-schema.yaml b/Documentation/devicetree/bindings/example-schema.yaml
new file mode 100644
index 000000000..b04f3cc43
--- /dev/null
+++ b/Documentation/devicetree/bindings/example-schema.yaml
@@ -0,0 +1,279 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2018 Linaro Ltd.
+%YAML 1.2
+---
+# All the top-level keys are standard json-schema keywords except for
+# 'maintainers' and 'select'
+
+# $id is a unique identifier based on the filename. There may or may not be a
+# file present at the URL.
+$id: http://devicetree.org/schemas/example-schema.yaml#
+# $schema is the meta-schema this schema should be validated with.
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: An Example Device
+
+maintainers:
+  - Rob Herring <robh@kernel.org>
+
+description: |
+  A more detailed multi-line description of the binding.
+
+  Details about the hardware device and any links to datasheets can go here.
+
+  Literal blocks are marked with the '|' at the beginning. The end is marked by
+  indentation less than the first line of the literal block. Lines also cannot
+  begin with a tab character.
+
+select: false
+  # 'select' is a schema applied to a DT node to determine if this binding
+  # schema should be applied to the node. It is optional and by default the
+  # possible compatible strings are extracted and used to match.
+
+  # In this case, a 'false' schema will never match.
+
+properties:
+  # A dictionary of DT properties for this binding schema
+  compatible:
+    # More complicated schema can use oneOf (XOR), anyOf (OR), or allOf (AND)
+    # to handle different conditions.
+    # In this case, it's needed to handle a variable number of values as there
+    # isn't another way to express a constraint of the last string value.
+    # The boolean schema must be a list of schemas.
+    oneOf:
+      - items:
+          # items is a list of possible values for the property. The number of
+          # values is determined by the number of elements in the list.
+          # Order in lists is significant, order in dicts is not
+          # Must be one of the 1st enums followed by the 2nd enum
+          #
+          # Each element in items should be 'enum' or 'const'
+          - enum:
+              - vendor,soc4-ip
+              - vendor,soc3-ip
+              - vendor,soc2-ip
+          - const: vendor,soc1-ip
+        # additionalItems being false is implied
+        # minItems/maxItems equal to 2 is implied
+      - items:
+          # 'const' is just a special case of an enum with a single possible value
+          - const: vendor,soc1-ip
+
+  reg:
+    # The core schema already checks that reg values are numbers, so device
+    # specific schema don't need to do those checks.
+    # The description of each element defines the order and implicitly defines
+    # the number of reg entries.
+    items:
+      - description: core registers
+      - description: aux registers
+    # minItems/maxItems equal to 2 is implied
+
+  reg-names:
+    # The core schema enforces this (*-names) is a string array
+    items:
+      - const: core
+      - const: aux
+
+  clocks:
+    # Cases that have only a single entry just need to express that with maxItems
+    maxItems: 1
+    description: bus clock. A description is only needed for a single item if
+      there's something unique to add.
+      The items should have a fixed order, so pattern matching names are
+      discouraged.
+
+  clock-names:
+    # For single-entry lists in clocks, resets etc., the xxx-names often do not
+    # bring any value, especially if they copy the IP block name.  In such case
+    # just skip the xxx-names.
+    items:
+      - const: bus
+
+  interrupts:
+    # Either 1 or 2 interrupts can be present
+    minItems: 1
+    items:
+      - description: tx or combined interrupt
+      - description: rx interrupt
+    description:
+      A variable number of interrupts warrants a description of what conditions
+      affect the number of interrupts. Otherwise, descriptions on standard
+      properties are not necessary.
+      The items should have a fixed order, so pattern matching names are
+      discouraged.
+
+  interrupt-names:
+    # minItems must be specified here because the default would be 2
+    minItems: 1
+    items:
+      - const: tx irq
+      - const: rx irq
+
+  # Property names starting with '#' must be quoted
+  '#interrupt-cells':
+    # A simple case where the value must always be '2'.
+    # The core schema handles that this must be a single integer.
+    const: 2
+
+  interrupt-controller: true
+    # The core checks this is a boolean, so just have to list it here to be
+    # valid for this binding.
+
+  clock-frequency:
+    # The type is set in the core schema. Per-device schema only need to set
+    # constraints on the possible values.
+    minimum: 100
+    maximum: 400000
+    # The value that should be used if the property is not present
+    default: 200
+
+  foo-gpios:
+    maxItems: 1
+    description: A connection of the 'foo' gpio line.
+
+  # *-supply is always a single phandle, so nothing more to define.
+  foo-supply: true
+
+  # Vendor-specific properties
+  #
+  # Vendor-specific properties have slightly different schema requirements than
+  # common properties. They must have at least a type definition and
+  # 'description'.
+  vendor,int-property:
+    description: Vendor-specific properties must have a description
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [2, 4, 6, 8, 10]
+
+  vendor,bool-property:
+    description: Vendor-specific properties must have a description. Boolean
+      properties are one case where the json-schema 'type' keyword can be used
+      directly.
+    type: boolean
+
+  vendor,string-array-property:
+    description: Vendor-specific properties should reference a type in the
+      core schema.
+    $ref: /schemas/types.yaml#/definitions/string-array
+    items:
+      - enum: [foo, bar]
+      - enum: [baz, boo]
+
+  vendor,property-in-standard-units-microvolt:
+    description: Vendor-specific properties having a standard unit suffix
+      don't need a type.
+    enum: [ 100, 200, 300 ]
+
+  vendor,int-array-variable-length-and-constrained-values:
+    description: Array might define what type of elements might be used (e.g.
+      their range).
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 2
+    maxItems: 3
+    items:
+      minimum: 0
+      maximum: 8
+
+  child-node:
+    description: Child nodes are just another property from a json-schema
+      perspective.
+    type: object  # DT nodes are json objects
+    # Child nodes also need additionalProperties or unevaluatedProperties, where
+    # 'false' should be used in most cases (see 'child-node-with-own-schema'
+    # below).
+    additionalProperties: false
+    properties:
+      vendor,a-child-node-property:
+        description: Child node properties have all the same schema
+          requirements.
+        type: boolean
+
+    required:
+      - vendor,a-child-node-property
+
+  child-node-with-own-schema:
+    description: |
+      Child node with their own compatible and device schema which ends in
+      'additionalProperties: false' or 'unevaluatedProperties: false' can
+      mention only the compatible and use here 'additionalProperties: true'.
+    type: object
+    additionalProperties: true
+    properties:
+      compatible:
+        const: vendor,sub-device
+
+# Describe the relationship between different properties
+dependencies:
+  # 'vendor,bool-property' is only allowed when 'vendor,string-array-property'
+  # is present
+  vendor,bool-property: [ 'vendor,string-array-property' ]
+  # Expressing 2 properties in both orders means all of the set of properties
+  # must be present or none of them.
+  vendor,string-array-property: [ 'vendor,bool-property' ]
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+
+# if/then schema can be used to handle conditions on a property affecting
+# another property. A typical case is a specific 'compatible' value changes the
+# constraints on other properties.
+#
+# For multiple 'if' schema, group them under an 'allOf'.
+#
+# If the conditionals become too unwieldy, then it may be better to just split
+# the binding into separate schema documents.
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: vendor,soc2-ip
+    then:
+      required:
+        - foo-supply
+    else:
+      # If otherwise the property is not allowed:
+      properties:
+        foo-supply: false
+  # Altering schema depending on presence of properties is usually done by
+  # dependencies (see above), however some adjustments might require if:
+  - if:
+      required:
+        - vendor,bool-property
+    then:
+      properties:
+        vendor,int-property:
+          enum: [2, 4, 6]
+
+# Ideally, the schema should have this line otherwise any other properties
+# present are allowed. There's a few common properties such as 'status' and
+# 'pinctrl-*' which are added automatically by the tooling.
+#
+# This can't be used in cases where another schema is referenced
+# (i.e. allOf: [{$ref: ...}]).
+# If and only if another schema is referenced and arbitrary children nodes can
+# appear, "unevaluatedProperties: false" could be used.  A typical example is
+# an I2C controller where no name pattern matching for children can be added.
+additionalProperties: false
+
+examples:
+  # Examples are now compiled with dtc and validated against the schemas
+  #
+  # Examples have a default #address-cells and #size-cells value of 1. This can
+  # be overridden or an appropriate parent bus node should be shown (such as on
+  # i2c buses).
+  #
+  # Any includes used have to be explicitly included. Use 4-space indentation.
+  - |
+    node@1000 {
+        compatible = "vendor,soc4-ip", "vendor,soc1-ip";
+        reg = <0x1000 0x80>,
+              <0x3000 0x80>;
+        reg-names = "core", "aux";
+        interrupts = <10>;
+        interrupt-controller;
+        #interrupt-cells = <2>;
+    };