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, 418 insertions, 0 deletions

diff --git a/Documentation/sphinx/maintainers_include.py b/Documentation/sphinx/maintainers_include.py
new file mode 100755
index 000000000..7ffe19b5e
--- /dev/null
+++ b/Documentation/sphinx/maintainers_include.py
@@ -0,0 +1,418 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: GPL-2.0
+# -*- coding: utf-8; mode: python -*-
+# pylint: disable=C0209, C0301, E0401, R0022, R0902, R0903, R0912, R0914
+
+"""
+Implementation of the ``maintainers-include`` reST-directive.
+
+:copyright:  Copyright (C) 2019  Kees Cook <keescook@chromium.org>
+:license:    GPL Version 2, June 1991 see linux/COPYING for details.
+
+The ``maintainers-include`` reST-directive performs extensive parsing
+specific to the Linux kernel's standard "MAINTAINERS" file, in an
+effort to avoid needing to heavily mark up the original plain text.
+"""
+
+import os.path
+import re
+
+from glob import glob
+
+from docutils import statemachine
+from docutils.parsers.rst.directives.misc import Include
+
+#
+# Base URL for intersphinx-like links to maintainer profiles
+#
+KERNELDOC_URL = "https://docs.kernel.org/"
+
+__version__ = "1.0"
+
+maint_parser = None  # pylint: disable=C0103
+
+JS_FILTER = """
+(function() {
+  function filterTable(table) {
+    const filter = document.getElementById("filter-table").value.trim();
+    const rows = table.querySelectorAll("tbody tr");
+    for (let i = 0; i < rows.length; i++) {
+      const tds = rows[i].getElementsByTagName("td");
+      let match = false;
+      for (let j = 0; j < tds.length; j++) {
+        const cellText = (tds[j].textContent || tds[j].innerText);
+        if (cellText.includes(filter)) {
+          match = true;
+          break;
+        }
+      }
+      rows[i].style.display = match ? "table-row" : "none";
+    }
+  }
+  function addInput() {
+    const table = document.getElementById("maintainers-table");
+    if (!table) return;
+    let input = document.getElementById("filter-table");
+    if (!input) {
+      const filt_div = document.createElement('div');
+      filt_div.innerHTML = `
+        <p>Filter:
+          <input type="search" id="filter-table" placeholder="search string"/>
+          subsystem or property (case-sensitive)
+        </p>
+      `;
+      table.parentNode.insertBefore(filt_div, table);
+      const input = document.getElementById("filter-table")
+      input.addEventListener('input', () => filterTable(table));
+    }
+  }
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', addInput);
+  } else {
+    addInput();
+  }
+})();
+"""
+
+
+# Shamelessly stolen from docutils
+def ErrorString(exc):  # pylint: disable=C0103, C0116
+    return f"{exc.__class__.__name}: {exc}"  # pylint: disable=W0212
+
+class MaintainersParser:
+    """Parse MAINTAINERS file(s) content"""
+
+    def __init__(self, base_dir, app_dir, path):
+        self.path = path
+
+        # Poor man's state machine.
+        self.descriptions = False
+        self.maintainers = False
+        self.subsystems = False
+
+        self.subsystem_name = None
+
+        self.base_dir = base_dir
+        self.app_dir = app_dir
+
+        self.re_doc = re.compile(r'(Documentation/(\S*)\.rst)')
+
+        #
+        # Output variables with maintainers content to be stored
+        #
+        self.profile_toc = set()
+        self.profile_entries = {}
+        self.header = ""
+        self.maint_entries = {}
+        self.fields = {}
+
+        prev = None
+        with open(path, "r", encoding="utf-8") as fp:
+            for line in fp:
+                if self.descriptions:
+                    self.parse_descriptions(line)
+                elif self.maintainers and not self.subsystems:
+                    if re.search('^[A-Z0-9]', line):
+                        self.subsystems = True
+                        self.parse_subsystems(line)
+                    else:
+                        self.header += line
+                elif self.subsystems:
+                    self.parse_subsystems(line)
+                else:
+                    self.header += line
+
+                # Update the state machine when we find heading separators.
+                if line.startswith("----------"):
+                    if prev.startswith("Descriptions"):
+                        self.descriptions = True
+                    if prev.startswith("Maintainers"):
+                        self.maintainers = True
+
+                # Retain previous line for state machine transitions.
+                prev = line
+
+    def get_entries(self, text):
+        """Generate refs to ReST files in Documentation/"""
+
+        if "Documentation/" not in text:
+            return None
+
+        if "*" in text or "?" in text:
+            m = self.re_doc.search(text)
+            if not m:
+                return None
+
+            doc_list = glob(os.path.join(self.base_dir, m.group(1)))
+        else:
+            doc_list = [text]
+
+        entries = {}
+        for doc in doc_list:
+            m = self.re_doc.search(doc)
+            if m:
+                fname = m.group(1)
+                ename = m.group(2)
+
+                entry = os.path.relpath(self.base_dir + fname, self.app_dir)
+                entry = entry.removesuffix(".rst")
+
+                if entry.startswith("../"):
+                    html = KERNELDOC_URL + ename + ".html"
+                    entries[entry] = f'`{ename} <{html}>`_'
+                else:
+                    entries[entry] = f'/{entry}'
+
+        return entries
+
+    def linkify(self, text):
+        """Return a list of doc files converted to cross-references"""
+
+        entries = self.get_entries(text)
+        if not entries:
+            return text
+
+        return self.re_doc.sub(", ".join(entries.values()), text)
+
+    def parse_descriptions(self, line):
+        """Handle contents of the descriptions section."""
+
+        # Have we reached the end of the preformatted Descriptions text?
+        if line.startswith("Maintainers"):
+            self.descriptions = False
+            self.header += "\n" + line
+            return
+
+        # Look for and record field letter to field name mappings:
+        #   R: Designated *reviewer*: FullName <address@domain>
+        m = re.match(r"\s+(\S):\s+(\S+)", line)
+        if m:
+            field = m.group(1)
+            details = m.group(2)
+
+            if field not in self.fields:
+                m = re.search(r"\*([^\*]+)\*", line)
+                if m:
+                    self.fields[field] = m.group(1)
+            elif field in ['F', 'N', 'X', 'K']:
+                line = line.replace(details, f'``{details}``')
+
+        self.header += "| " + self.linkify(line)
+
+
+    def parse_subsystems(self, line):
+        """Handle contents of the per-subsystem sections."""
+
+        # Drop needless input whitespace.
+        line = line.rstrip()
+
+        # Skip empty lines: subsystem parser adds them as needed.
+        if not line:
+            return
+
+        if line[1] != ':':
+            self.subsystem_name = re.sub(r"\s+", " ", self.linkify(line))
+            return
+
+        # Render a subsystem field as:
+        #   :Field: entry
+        #           entry...
+        field, details = line.split(":", 1)
+        details = details.strip()
+
+        #
+        # Handle profile entries - either as files or as https refs
+        #
+        if field == "P":
+            entries = self.get_entries(details)
+            if entries:
+                for e, link in entries.items():
+                    if "html" not in link:
+                        self.profile_toc.add(e)
+
+                    self.profile_entries[self.subsystem_name] = link
+
+                details = ", ".join(entries.values())
+            else:
+                match = re.match(r"(https?://.*)", details)
+                if match:
+                    entry = match.group(1).strip()
+                    self.profile_entries[self.subsystem_name] = entry
+                else:
+                    self.profile_entries[self.subsystem_name] = f"``{details}``"
+
+                details = self.linkify(details)
+        else:
+            details = self.linkify(details)
+
+        #
+        # Mark paths (and regexes) as literal text for improved
+        # readability and to escape any escapes.
+        #
+        if field in ['F', 'N', 'X', 'K']:
+            # But only if not already marked :)
+            if ':doc:' not in details and "http" not in details:
+                details = '``%s``' % (details)
+
+        if self.subsystem_name not in self.maint_entries:
+            self.maint_entries[self.subsystem_name] = {}
+
+        if field not in self.maint_entries[self.subsystem_name]:
+            self.maint_entries[self.subsystem_name][field] = []
+
+        self.maint_entries[self.subsystem_name][field].append(details)
+
+        self.field_prev = field
+
+
+class MaintainersInclude(Include):
+    """MaintainersInclude (``maintainers-include``) directive"""
+
+    required_arguments = 0
+
+    def emit(self):
+        """Parse all the MAINTAINERS lines into ReST for human-readability"""
+        path = maint_parser.path
+        output = ".. _maintainers:\n\n"
+        output += maint_parser.header
+
+        output += ".. _maintainers_table:\n\n"
+        output += ".. flat-table::\n"
+        output += "  :header-rows: 1\n\n"
+        output += "  * - Subsystem\n"
+        output += "    - Properties\n\n"
+
+        self.state.document['maintainers_included'] = True
+
+        # Keep the last entry ("THE REST") in the end
+        entries = list(maint_parser.maint_entries.keys())
+        entries = sorted(entries[:-1], key=str.casefold) + [entries[-1]]
+
+        for name in entries:
+            fields = maint_parser.maint_entries[name]
+            output += f"  * - {name}\n"
+            tag = "-"
+            for field, lines in fields.items():
+                field_name = maint_parser.fields.get(field, field)
+
+                output += f"    {tag} :{field_name}:\n        "
+                output += ",\n        ".join(lines) + "\n"
+                tag = " "
+
+            output += "\n"
+
+        # For debugging the pre-rendered results...
+        #print(output, file=open("/tmp/MAINTAINERS.rst", "w"))
+
+        self.state.document.settings.record_dependencies.add(path)
+        self.state_machine.insert_input(statemachine.string2lines(output), path)
+
+    def run(self):
+        """Include the MAINTAINERS file as part of this reST file."""
+        if not self.state.document.settings.file_insertion_enabled:
+            raise self.warning('"%s" directive disabled.' % self.name)
+
+        try:
+            self.emit()
+        except IOError as error:
+            raise self.severe('Problems with "%s" directive path:\n%s.' %
+                      (self.name, ErrorString(error)))
+
+        return []
+
+
+class MaintainersProfile(Include):
+    """Generate a list with all maintainer's profiles"""
+
+    required_arguments = 0
+
+    def emit(self):
+        """Parse all the MAINTAINERS lines looking for profile entries"""
+        env = self.state.document.settings.env
+        docdir = os.path.dirname(os.path.join(env.srcdir, env.docname))
+        path = maint_parser.path
+
+        #
+        # Produce a list with all maintainer profiles, sorted by subsystem name
+        #
+        output = ""
+        for profile, entry in sorted(maint_parser.profile_entries.items()):
+            name = profile.title()
+
+            if entry.startswith("http"):
+                output += f"- `{name} <{entry}>`_\n"
+            elif entry.startswith("`"):
+                output += f"- {name}: {entry}\n"
+                self.warning(f"{profile}: Invalid 'P' tag: {entry}\n")
+            else:
+                if not name:
+                    name = entry
+
+                output += f"- :doc:`{name} <{entry}>`\n"
+
+        #
+        # Create a hidden TOC table with all profiles. That allows adding
+        # profiles without needing to add them on any index.rst file.
+        #
+        output += "\n.. toctree::\n"
+        output += "   :hidden:\n\n"
+
+        for f in sorted(maint_parser.profile_toc):
+            fname = os.path.join(maint_parser.base_dir, "Documentation", f)
+            fname = os.path.relpath(fname, docdir)
+            output += f"   {fname}\n"
+
+        output += "\n"
+
+        # For debugging the pre-rendered results...
+        #print(output, file=open("/tmp/profiles.rst", "w"))
+
+        self.state.document.settings.record_dependencies.add(path)
+        self.state_machine.insert_input(statemachine.string2lines(output), path)
+
+    def run(self):
+        """Include the MAINTAINERS file as part of this reST file."""
+        if not self.state.document.settings.file_insertion_enabled:
+            raise self.warning('"%s" directive disabled.' % self.name)
+
+        try:
+            self.emit()
+        except IOError as error:
+            raise self.severe('Problems with "%s" directive path:\n%s.' %
+                      (self.name, ErrorString(error)))
+
+        return []
+
+
+# pylint: disable=W0613
+def add_filter_script(app, pagename, templatename, context, doctree):
+    """Add Filter javascript only to maintainers page"""
+
+    if doctree and doctree.get('maintainers_included'):
+        app.add_js_file(None, body=JS_FILTER)
+
+
+def setup(app):
+    """Setup Sphinx extension"""
+    global maint_parser  # pylint: disable=W0603
+
+    app_dir = os.path.abspath(app.srcdir)
+    match = re.match(r"(.*/)Documentation", app_dir)
+    if not match:
+        raise ValueError('Documentation directory not found.')
+
+    base_dir = match.group(1)
+    path = os.path.join(base_dir, "MAINTAINERS")
+
+    maint_parser = MaintainersParser(base_dir, app_dir, path)
+
+    app.add_directive("maintainers-include", MaintainersInclude)
+    app.add_directive("maintainers-profile-toc", MaintainersProfile)
+
+    app.connect("html-page-context", add_filter_script)
+
+    return {
+        "version": __version__,
+        "parallel_read_safe": True,
+        "parallel_write_safe": True,
+    }