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, 527 insertions, 0 deletions

diff --git a/Documentation/sphinx/kernel_include.py b/Documentation/sphinx/kernel_include.py
new file mode 100755
index 000000000..626762ff6
--- /dev/null
+++ b/Documentation/sphinx/kernel_include.py
@@ -0,0 +1,527 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# pylint: disable=R0903, R0912, R0914, R0915, C0209,W0707
+
+
+"""
+Implementation of the ``kernel-include`` reST-directive.
+
+:copyright:  Copyright (C) 2016  Markus Heiser
+:license:    GPL Version 2, June 1991 see linux/COPYING for details.
+
+The ``kernel-include`` reST-directive is a replacement for the ``include``
+directive. The ``kernel-include`` directive expand environment variables in
+the path name and allows to include files from arbitrary locations.
+
+.. hint::
+
+    Including files from arbitrary locations (e.g. from ``/etc``) is a
+    security risk for builders. This is why the ``include`` directive from
+    docutils *prohibit* pathnames pointing to locations *above* the filesystem
+    tree where the reST document with the include directive is placed.
+
+Substrings of the form $name or ${name} are replaced by the value of
+environment variable name. Malformed variable names and references to
+non-existing variables are left unchanged.
+
+**Supported Sphinx Include Options**:
+
+:param literal:
+    If present, the included file is inserted as a literal block.
+
+:param code:
+    Specify the language for syntax highlighting (e.g., 'c', 'python').
+
+:param encoding:
+    Specify the encoding of the included file (default: 'utf-8').
+
+:param tab-width:
+    Specify the number of spaces that a tab represents.
+
+:param start-line:
+    Line number at which to start including the file (1-based).
+
+:param end-line:
+    Line number at which to stop including the file (inclusive).
+
+:param start-after:
+    Include lines after the first line matching this text.
+
+:param end-before:
+    Include lines before the first line matching this text.
+
+:param number-lines:
+    Number the included lines (integer specifies start number).
+    Only effective with 'literal' or 'code' options.
+
+:param class:
+    Specify HTML class attribute for the included content.
+
+**Kernel-specific Extensions**:
+
+:param generate-cross-refs:
+    If present, instead of directly including the file, it calls
+    ParseDataStructs() to convert C data structures into cross-references
+    that link to comprehensive documentation in other ReST files.
+
+:param exception-file:
+    (Used with generate-cross-refs)
+
+    Path to a file containing rules for handling special cases:
+    - Ignore specific C data structures
+    - Use alternative reference names
+    - Specify different reference types
+
+:param warn-broken:
+    (Used with generate-cross-refs)
+
+    Enables warnings when auto-generated cross-references don't point to
+    existing documentation targets.
+"""
+
+# ==============================================================================
+# imports
+# ==============================================================================
+
+import os.path
+import re
+import sys
+
+from difflib import get_close_matches
+
+from docutils import io, nodes, statemachine
+from docutils.statemachine import ViewList
+from docutils.parsers.rst import Directive, directives
+from docutils.parsers.rst.directives.body import CodeBlock, NumberLines
+
+from sphinx.util import logging
+
+srctree = os.path.abspath(os.environ["srctree"])
+sys.path.insert(0, os.path.join(srctree, "tools/lib/python"))
+
+from kdoc.parse_data_structs import ParseDataStructs
+
+__version__ = "1.0"
+logger = logging.getLogger(__name__)
+
+RE_DOMAIN_REF = re.compile(r'\\ :(ref|c:type|c:func):`([^<`]+)(?:<([^>]+)>)?`\\')
+RE_SIMPLE_REF = re.compile(r'`([^`]+)`')
+RE_LINENO_REF = re.compile(r'^\s*-\s+LINENO_(\d+):\s+(.*)')
+RE_SPLIT_DOMAIN = re.compile(r"(.*)\.(.*)")
+
+def ErrorString(exc):  # Shamelessly stolen from docutils
+    return f'{exc.__class__.__name}: {exc}'
+
+
+# ==============================================================================
+class KernelInclude(Directive):
+    """
+    KernelInclude (``kernel-include``) directive
+
+    Most of the stuff here came from Include directive defined at:
+        docutils/parsers/rst/directives/misc.py
+
+    Yet, overriding the class don't has any benefits: the original class
+    only have run() and argument list. Not all of them are implemented,
+    when checked against latest Sphinx version, as with time more arguments
+    were added.
+
+    So, keep its own list of supported arguments
+    """
+
+    required_arguments = 1
+    optional_arguments = 0
+    final_argument_whitespace = True
+    option_spec = {
+        'literal': directives.flag,
+        'code': directives.unchanged,
+        'encoding': directives.encoding,
+        'tab-width': int,
+        'start-line': int,
+        'end-line': int,
+        'start-after': directives.unchanged_required,
+        'end-before': directives.unchanged_required,
+        # ignored except for 'literal' or 'code':
+        'number-lines': directives.unchanged,  # integer or None
+        'class': directives.class_option,
+
+        # Arguments that aren't from Sphinx Include directive
+        'generate-cross-refs': directives.flag,
+        'warn-broken': directives.flag,
+        'toc': directives.flag,
+        'exception-file': directives.unchanged,
+    }
+
+    def read_rawtext(self, path, encoding):
+            """Read and process file content with error handling"""
+            try:
+                self.state.document.settings.record_dependencies.add(path)
+                include_file = io.FileInput(source_path=path,
+                                            encoding=encoding,
+                                            error_handler=self.state.document.settings.input_encoding_error_handler)
+            except UnicodeEncodeError:
+                raise self.severe('Problems with directive path:\n'
+                                'Cannot encode input file path "%s" '
+                                '(wrong locale?).' % path)
+            except IOError as error:
+                raise self.severe('Problems with directive path:\n%s.' % ErrorString(error))
+
+            try:
+                return include_file.read()
+            except UnicodeError as error:
+                raise self.severe('Problem with directive:\n%s' % ErrorString(error))
+
+    def apply_range(self, rawtext):
+        """
+        Handles start-line, end-line, start-after and end-before parameters
+        """
+
+        # Get to-be-included content
+        startline = self.options.get('start-line', None)
+        endline = self.options.get('end-line', None)
+        try:
+            if startline or (endline is not None):
+                lines = rawtext.splitlines()
+                rawtext = '\n'.join(lines[startline:endline])
+        except UnicodeError as error:
+            raise self.severe(f'Problem with "{self.name}" directive:\n'
+                              + io.error_string(error))
+        # start-after/end-before: no restrictions on newlines in match-text,
+        # and no restrictions on matching inside lines vs. line boundaries
+        after_text = self.options.get("start-after", None)
+        if after_text:
+            # skip content in rawtext before *and incl.* a matching text
+            after_index = rawtext.find(after_text)
+            if after_index < 0:
+                raise self.severe('Problem with "start-after" option of "%s" '
+                                  "directive:\nText not found." % self.name)
+            rawtext = rawtext[after_index + len(after_text) :]
+        before_text = self.options.get("end-before", None)
+        if before_text:
+            # skip content in rawtext after *and incl.* a matching text
+            before_index = rawtext.find(before_text)
+            if before_index < 0:
+                raise self.severe('Problem with "end-before" option of "%s" '
+                                  "directive:\nText not found." % self.name)
+            rawtext = rawtext[:before_index]
+
+        return rawtext
+
+    def xref_text(self, env, path, tab_width):
+        """
+        Read and add contents from a C file parsed to have cross references.
+
+        There are two types of supported output here:
+        - A C source code with cross-references;
+        - a TOC table containing cross references.
+        """
+        parser = ParseDataStructs()
+
+        if 'exception-file' in self.options:
+            source_dir = os.path.dirname(os.path.abspath(
+                self.state_machine.input_lines.source(
+                    self.lineno - self.state_machine.input_offset - 1)))
+            exceptions_file = os.path.join(source_dir, self.options['exception-file'])
+        else:
+            exceptions_file = None
+
+        parser.parse_file(path, exceptions_file)
+
+        # Store references on a symbol dict to be used at check time
+        if 'warn-broken' in self.options:
+            env._xref_files.add(path)
+
+        if "toc" not in self.options:
+
+            rawtext = ".. parsed-literal::\n\n" + parser.gen_output()
+            self.apply_range(rawtext)
+
+            include_lines = statemachine.string2lines(rawtext, tab_width,
+                                                      convert_whitespace=True)
+
+            # Sphinx always blame the ".. <directive>", so placing
+            # line numbers here won't make any difference
+
+            self.state_machine.insert_input(include_lines, path)
+            return []
+
+        # TOC output is a ReST file, not a literal. So, we can add line
+        # numbers
+
+        startline = self.options.get('start-line', None)
+        endline = self.options.get('end-line', None)
+
+        relpath = os.path.relpath(path, srctree)
+
+        result = ViewList()
+        for line in parser.gen_toc().split("\n"):
+            match = RE_LINENO_REF.match(line)
+            if not match:
+                result.append(line, path)
+                continue
+
+            ln, ref = match.groups()
+            ln = int(ln)
+
+            # Filter line range if needed
+            if startline and (ln < startline):
+                continue
+
+            if endline and (ln > endline):
+                continue
+
+            # Sphinx numerates starting with zero, but text editors
+            # and other tools start from one
+            realln = ln + 1
+            result.append(f"- {ref}: {relpath}#{realln}", path, ln)
+
+        self.state_machine.insert_input(result, path)
+
+        return []
+
+    def literal(self, path, tab_width, rawtext):
+        """Output a literal block"""
+
+        # Convert tabs to spaces, if `tab_width` is positive.
+        if tab_width >= 0:
+            text = rawtext.expandtabs(tab_width)
+        else:
+            text = rawtext
+        literal_block = nodes.literal_block(rawtext, source=path,
+                                            classes=self.options.get("class", []))
+        literal_block.line = 1
+        self.add_name(literal_block)
+        if "number-lines" in self.options:
+            try:
+                startline = int(self.options["number-lines"] or 1)
+            except ValueError:
+                raise self.error(":number-lines: with non-integer start value")
+            endline = startline + len(include_lines)
+            if text.endswith("\n"):
+                text = text[:-1]
+            tokens = NumberLines([([], text)], startline, endline)
+            for classes, value in tokens:
+                if classes:
+                    literal_block += nodes.inline(value, value,
+                                                    classes=classes)
+                else:
+                    literal_block += nodes.Text(value, value)
+        else:
+            literal_block += nodes.Text(text, text)
+        return [literal_block]
+
+    def code(self, path, tab_width):
+        """Output a code block"""
+
+        include_lines = statemachine.string2lines(rawtext, tab_width,
+                                                  convert_whitespace=True)
+
+        self.options["source"] = path
+        codeblock = CodeBlock(self.name,
+                                [self.options.pop("code")],  # arguments
+                                self.options,
+                                include_lines,
+                                self.lineno,
+                                self.content_offset,
+                                self.block_text,
+                                self.state,
+                                self.state_machine)
+        return codeblock.run()
+
+    def run(self):
+        """Include a file as part of the content of this reST file."""
+        env = self.state.document.settings.env
+
+        #
+        # The include logic accepts only patches relative to the
+        # Kernel source tree.  The logic does check it to prevent
+        # directory traverse issues.
+        #
+
+        srctree = os.path.abspath(os.environ["srctree"])
+
+        path = os.path.expandvars(self.arguments[0])
+        src_path = os.path.join(srctree, path)
+
+        if os.path.isfile(src_path):
+            base = srctree
+            path = src_path
+        else:
+            raise self.warning(f'File "%s" doesn\'t exist', path)
+
+        abs_base = os.path.abspath(base)
+        abs_full_path = os.path.abspath(os.path.join(base, path))
+
+        try:
+            if os.path.commonpath([abs_full_path, abs_base]) != abs_base:
+                raise self.severe('Problems with "%s" directive, prohibited path: %s' %
+                                  (self.name, path))
+        except ValueError:
+            # Paths don't have the same drive (Windows) or other incompatibility
+            raise self.severe('Problems with "%s" directive, invalid path: %s' %
+                            (self.name, path))
+
+        self.arguments[0] = path
+
+        #
+        # Add path location to Sphinx dependencies to ensure proper cache
+        # invalidation check.
+        #
+
+        env.note_dependency(os.path.abspath(path))
+
+        if not self.state.document.settings.file_insertion_enabled:
+            raise self.warning('"%s" directive disabled.' % self.name)
+        source = self.state_machine.input_lines.source(self.lineno -
+                                                       self.state_machine.input_offset - 1)
+        source_dir = os.path.dirname(os.path.abspath(source))
+        path = directives.path(self.arguments[0])
+        if path.startswith("<") and path.endswith(">"):
+            path = os.path.join(self.standard_include_path, path[1:-1])
+        path = os.path.normpath(os.path.join(source_dir, path))
+
+        # HINT: this is the only line I had to change / commented out:
+        # path = utils.relative_path(None, path)
+
+        encoding = self.options.get("encoding",
+                                    self.state.document.settings.input_encoding)
+        tab_width = self.options.get("tab-width",
+                                     self.state.document.settings.tab_width)
+
+        # Get optional arguments to related to cross-references generation
+        if "generate-cross-refs" in self.options:
+            return self.xref_text(env, path, tab_width)
+
+        rawtext = self.read_rawtext(path, encoding)
+        rawtext = self.apply_range(rawtext)
+
+        if "code" in self.options:
+            return self.code(path, tab_width, rawtext)
+
+        return self.literal(path, tab_width, rawtext)
+
+# ==============================================================================
+
+reported = set()
+DOMAIN_INFO = {}
+all_refs = {}
+
+def fill_domain_info(env):
+    """
+    Get supported reference types for each Sphinx domain and C namespaces
+    """
+    if DOMAIN_INFO:
+        return
+
+    for domain_name, domain_instance in env.domains.items():
+        try:
+            object_types = list(domain_instance.object_types.keys())
+            DOMAIN_INFO[domain_name] = object_types
+        except AttributeError:
+            # Ignore domains that we can't retrieve object types, if any
+            pass
+
+    for domain in DOMAIN_INFO.keys():
+        domain_obj = env.get_domain(domain)
+        for name, dispname, objtype, docname, anchor, priority in domain_obj.get_objects():
+            ref_name = name.lower()
+
+            if domain == "c":
+                if '.' in ref_name:
+                    ref_name = ref_name.split(".")[-1]
+
+            if not ref_name in all_refs:
+                all_refs[ref_name] = []
+
+            all_refs[ref_name].append(f"\t{domain}:{objtype}:`{name}` (from {docname})")
+
+def get_suggestions(app, env, node,
+                    original_target, original_domain, original_reftype):
+    """Check if target exists in the other domain or with different reftypes."""
+    original_target = original_target.lower()
+
+    # Remove namespace if present
+    if original_domain == "c":
+        if '.' in original_target:
+            original_target = original_target.split(".")[-1]
+
+    suggestions = []
+
+    # If name exists, propose exact name match on different domains
+    if original_target in all_refs:
+        return all_refs[original_target]
+
+    # If not found, get a close match, using difflib.
+    # Such method is based on Ratcliff-Obershelp Algorithm, which seeks
+    # for a close match within a certain distance. We're using the defaults
+    # here, e.g. cutoff=0.6, proposing 3 alternatives
+    matches = get_close_matches(original_target, all_refs.keys())
+    for match in matches:
+        suggestions += all_refs[match]
+
+    return suggestions
+
+def check_missing_refs(app, env, node, contnode):
+    """Check broken refs for the files it creates xrefs"""
+    if not node.source:
+        return None
+
+    try:
+        xref_files = env._xref_files
+    except AttributeError:
+        logger.critical("FATAL: _xref_files not initialized!")
+        raise
+
+    # Only show missing references for kernel-include reference-parsed files
+    if node.source not in xref_files:
+        return None
+
+    fill_domain_info(env)
+
+    target = node.get('reftarget', '')
+    domain = node.get('refdomain', 'std')
+    reftype = node.get('reftype', '')
+
+    msg = f"Invalid xref: {domain}:{reftype}:`{target}`"
+
+    # Don't duplicate warnings
+    data = (node.source, msg)
+    if data in reported:
+        return None
+    reported.add(data)
+
+    suggestions = get_suggestions(app, env, node, target, domain, reftype)
+    if suggestions:
+        msg += ". Possible alternatives:\n" + '\n'.join(suggestions)
+
+    logger.warning(msg, location=node, type='ref', subtype='missing')
+
+    return None
+
+def merge_xref_info(app, env, docnames, other):
+    """
+    As each process modify env._xref_files, we need to merge them back.
+    """
+    if not hasattr(other, "_xref_files"):
+        return
+    env._xref_files.update(getattr(other, "_xref_files", set()))
+
+def init_xref_docs(app, env, docnames):
+    """Initialize a list of files that we're generating cross references¨"""
+    app.env._xref_files = set()
+
+# ==============================================================================
+
+def setup(app):
+    """Setup Sphinx exension"""
+
+    app.connect("env-before-read-docs", init_xref_docs)
+    app.connect("env-merge-info", merge_xref_info)
+    app.add_directive("kernel-include", KernelInclude)
+    app.connect("missing-reference", check_missing_refs)
+
+    return {
+        "version": __version__,
+        "parallel_read_safe": True,
+        "parallel_write_safe": True,
+    }