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, 617 insertions, 0 deletions

diff --git a/Documentation/conf.py b/Documentation/conf.py
new file mode 100644
index 000000000..5ab26ce89
--- /dev/null
+++ b/Documentation/conf.py
@@ -0,0 +1,617 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# pylint: disable=C0103,C0209
+
+"""
+The Linux Kernel documentation build configuration file.
+"""
+
+import os
+import shutil
+import sys
+
+from  textwrap import dedent
+
+import sphinx
+
+# Location of Documentation/ directory
+kern_doc_dir = os.path.dirname(os.path.abspath(__file__))
+
+# Add location of Sphinx extensions
+sys.path.insert(0, os.path.join(kern_doc_dir, "sphinx"))
+
+# Allow sphinx.ext.autodoc to document files at tools and scripts
+sys.path.append(os.path.join(kern_doc_dir, "..", "tools"))
+sys.path.append(os.path.join(kern_doc_dir, "..", "scripts"))
+
+# Minimal supported version
+needs_sphinx = "3.4.3"
+
+# Get Sphinx version
+major, minor, patch = sphinx.version_info[:3]          # pylint: disable=I1101
+
+# Include_patterns were added on Sphinx 5.1
+if (major < 5) or (major == 5 and minor < 1):
+    has_include_patterns = False
+else:
+    has_include_patterns = True
+    # Include patterns that don't contain directory names, in glob format
+    include_patterns = ["**.rst"]
+
+# Exclude of patterns that don't contain directory names, in glob format.
+exclude_patterns = []
+
+# List of patterns that contain directory names in glob format.
+dyn_include_patterns = []
+dyn_exclude_patterns = ["output", "sphinx-includes"]
+
+# Currently, only netlink/specs has a parser for yaml.
+# Prefer using include patterns if available, as it is faster
+if has_include_patterns:
+    dyn_include_patterns.append("netlink/specs/*.yaml")
+else:
+    dyn_exclude_patterns.append("netlink/*.yaml")
+    dyn_exclude_patterns.append("devicetree/bindings/**.yaml")
+    dyn_exclude_patterns.append("core-api/kho/bindings/**.yaml")
+
+# Link to man pages
+manpages_url = 'https://man7.org/linux/man-pages/man{section}/{page}.{section}.html'
+
+# Properly handle directory patterns and LaTeX docs
+# -------------------------------------------------
+
+def config_init(app, config):
+    """
+    Initialize path-dependent variables
+
+    On Sphinx, all directories are relative to what it is passed as
+    SOURCEDIR parameter for sphinx-build. Due to that, all patterns
+    that have directory names on it need to be dynamically set, after
+    converting them to a relative path.
+
+    As Sphinx doesn't include any patterns outside SOURCEDIR, we should
+    exclude relative patterns that start with "../".
+    """
+
+    # setup include_patterns dynamically
+    if has_include_patterns:
+        for p in dyn_include_patterns:
+            full = os.path.join(kern_doc_dir, p)
+
+            rel_path = os.path.relpath(full, start=app.srcdir)
+            if rel_path.startswith("../"):
+                continue
+
+            config.include_patterns.append(rel_path)
+
+    # setup exclude_patterns dynamically
+    for p in dyn_exclude_patterns:
+        full = os.path.join(kern_doc_dir, p)
+
+        rel_path = os.path.relpath(full, start=app.srcdir)
+        if rel_path.startswith("../"):
+            continue
+
+        config.exclude_patterns.append(rel_path)
+
+    # LaTeX and PDF output require a list of documents with are dependent
+    # of the app.srcdir. Add them here
+
+    # Handle the case where SPHINXDIRS is used
+    if not os.path.samefile(kern_doc_dir, app.srcdir):
+        # Add a tag to mark that the build is actually a subproject
+        tags.add("subproject")
+
+        # get index.rst, if it exists
+        doc = os.path.basename(app.srcdir)
+        fname = "index"
+        if os.path.exists(os.path.join(app.srcdir, fname + ".rst")):
+            latex_documents.append((fname, doc + ".tex",
+                                    "Linux %s Documentation" % doc.capitalize(),
+                                    "The kernel development community",
+                                    "manual"))
+            return
+
+    # When building all docs, or when a main index.rst doesn't exist, seek
+    # for it on subdirectories
+    for doc in os.listdir(app.srcdir):
+        fname = os.path.join(doc, "index")
+        if not os.path.exists(os.path.join(app.srcdir, fname + ".rst")):
+            continue
+
+        has = False
+        for l in latex_documents:
+            if l[0] == fname:
+                has = True
+                break
+
+        if not has:
+            latex_documents.append((fname, doc + ".tex",
+                                    "Linux %s Documentation" % doc.capitalize(),
+                                    "The kernel development community",
+                                    "manual"))
+
+# helper
+# ------
+
+
+def have_command(cmd):
+    """Search ``cmd`` in the ``PATH`` environment.
+
+    If found, return True.
+    If not found, return False.
+    """
+    return shutil.which(cmd) is not None
+
+
+# -- General configuration ------------------------------------------------
+
+# Add any Sphinx extensions in alphabetic order
+extensions = [
+    "automarkup",
+    "kernel_abi",
+    "kerneldoc",
+    "kernel_feat",
+    "kernel_include",
+    "kfigure",
+    "maintainers_include",
+    "parser_yaml",
+    "rstFlatTable",
+    "sphinx.ext.autodoc",
+    "sphinx.ext.autosectionlabel",
+    "sphinx.ext.ifconfig",
+    "translations",
+]
+# Since Sphinx version 3, the C function parser is more pedantic with regards
+# to type checking. Due to that, having macros at c:function cause problems.
+# Those needed to be escaped by using c_id_attributes[] array
+c_id_attributes = [
+    # GCC Compiler types not parsed by Sphinx:
+    "__restrict__",
+
+    # include/linux/compiler_types.h:
+    "__iomem",
+    "__kernel",
+    "noinstr",
+    "notrace",
+    "__percpu",
+    "__rcu",
+    "__user",
+    "__force",
+    "__counted_by_le",
+    "__counted_by_be",
+
+    # include/linux/compiler_attributes.h:
+    "__alias",
+    "__aligned",
+    "__aligned_largest",
+    "__always_inline",
+    "__assume_aligned",
+    "__cold",
+    "__attribute_const__",
+    "__copy",
+    "__pure",
+    "__designated_init",
+    "__visible",
+    "__printf",
+    "__scanf",
+    "__gnu_inline",
+    "__malloc",
+    "__mode",
+    "__no_caller_saved_registers",
+    "__noclone",
+    "__nonstring",
+    "__noreturn",
+    "__packed",
+    "__pure",
+    "__section",
+    "__always_unused",
+    "__maybe_unused",
+    "__used",
+    "__weak",
+    "noinline",
+    "__fix_address",
+    "__counted_by",
+
+    # include/linux/memblock.h:
+    "__init_memblock",
+    "__meminit",
+
+    # include/linux/init.h:
+    "__init",
+    "__ref",
+
+    # include/linux/linkage.h:
+    "asmlinkage",
+
+    # include/linux/btf.h
+    "__bpf_kfunc",
+]
+
+# Ensure that autosectionlabel will produce unique names
+autosectionlabel_prefix_document = True
+autosectionlabel_maxdepth = 2
+
+# Load math renderer:
+# For html builder, load imgmath only when its dependencies are met.
+# mathjax is the default math renderer since Sphinx 1.8.
+have_latex = have_command("latex")
+have_dvipng = have_command("dvipng")
+load_imgmath = have_latex and have_dvipng
+
+# Respect SPHINX_IMGMATH (for html docs only)
+if "SPHINX_IMGMATH" in os.environ:
+    env_sphinx_imgmath = os.environ["SPHINX_IMGMATH"]
+    if "yes" in env_sphinx_imgmath:
+        load_imgmath = True
+    elif "no" in env_sphinx_imgmath:
+        load_imgmath = False
+    else:
+        sys.stderr.write("Unknown env SPHINX_IMGMATH=%s ignored.\n" % env_sphinx_imgmath)
+
+if load_imgmath:
+    extensions.append("sphinx.ext.imgmath")
+    math_renderer = "imgmath"
+else:
+    math_renderer = "mathjax"
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ["sphinx/templates"]
+
+# The suffixes of source filenames that will be automatically parsed
+source_suffix = {
+    ".rst": "restructuredtext",
+    ".yaml": "yaml",
+}
+
+# The encoding of source files.
+# source_encoding = 'utf-8-sig'
+
+# The master toctree document.
+master_doc = "index"
+
+# General information about the project.
+project = "The Linux Kernel"
+copyright = "The kernel development community"         # pylint: disable=W0622
+author = "The kernel development community"
+
+# The version info for the project you're documenting, acts as replacement for
+# |version| and |release|, also used in various other places throughout the
+# built documents.
+#
+# In a normal build, version and release are set to KERNELVERSION and
+# KERNELRELEASE, respectively, from the Makefile via Sphinx command line
+# arguments.
+#
+# The following code tries to extract the information by reading the Makefile,
+# when Sphinx is run directly (e.g. by Read the Docs).
+try:
+    makefile_version = None
+    makefile_patchlevel = None
+    with open("../Makefile", encoding="utf-8") as fp:
+        for line in fp:
+            key, val = [x.strip() for x in line.split("=", 2)]
+            if key == "VERSION":
+                makefile_version = val
+            elif key == "PATCHLEVEL":
+                makefile_patchlevel = val
+            if makefile_version and makefile_patchlevel:
+                break
+except Exception:
+    pass
+finally:
+    if makefile_version and makefile_patchlevel:
+        version = release = makefile_version + "." + makefile_patchlevel
+    else:
+        version = release = "unknown version"
+
+
+def get_cline_version():
+    """
+    HACK: There seems to be no easy way for us to get at the version and
+    release information passed in from the makefile...so go pawing through the
+    command-line options and find it for ourselves.
+    """
+
+    c_version = c_release = ""
+    for arg in sys.argv:
+        if arg.startswith("version="):
+            c_version = arg[8:]
+        elif arg.startswith("release="):
+            c_release = arg[8:]
+    if c_version:
+        if c_release:
+            return c_version + "-" + c_release
+        return c_version
+    return version  # Whatever we came up with before
+
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#
+# This is also used if you do content translation via gettext catalogs.
+# Usually you set "language" from the command line for these cases.
+language = "en"
+
+# There are two options for replacing |today|: either, you set today to some
+# non-false value, then it is used:
+# today = ''
+# Else, today_fmt is used as the format for a strftime call.
+# today_fmt = '%B %d, %Y'
+
+# The reST default role (used for this markup: `text`) to use for all
+# documents.
+# default_role = None
+
+# If true, '()' will be appended to :func: etc. cross-reference text.
+# add_function_parentheses = True
+
+# If true, the current module name will be prepended to all description
+# unit titles (such as .. function::).
+# add_module_names = True
+
+# If true, sectionauthor and moduleauthor directives will be shown in the
+# output. They are ignored by default.
+# show_authors = False
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = "sphinx"
+
+# A list of ignored prefixes for module index sorting.
+# modindex_common_prefix = []
+
+# If true, keep warnings as "system message" paragraphs in the built documents.
+# keep_warnings = False
+
+# If true, `todo` and `todoList` produce output, else they produce nothing.
+todo_include_todos = False
+
+primary_domain = "c"
+highlight_language = "none"
+
+# -- Options for HTML output ----------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+
+# Default theme
+html_theme = "alabaster"
+html_css_files = []
+
+if "DOCS_THEME" in os.environ:
+    html_theme = os.environ["DOCS_THEME"]
+
+if html_theme in ["sphinx_rtd_theme", "sphinx_rtd_dark_mode"]:
+    # Read the Docs theme
+    try:
+        import sphinx_rtd_theme
+
+        html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
+
+        # Add any paths that contain custom static files (such as style sheets) here,
+        # relative to this directory. They are copied after the builtin static files,
+        # so a file named "default.css" will overwrite the builtin "default.css".
+        html_css_files = [
+            "theme_overrides.css",
+        ]
+
+        # Read the Docs dark mode override theme
+        if html_theme == "sphinx_rtd_dark_mode":
+            try:
+                import sphinx_rtd_dark_mode            # pylint: disable=W0611
+
+                extensions.append("sphinx_rtd_dark_mode")
+            except ImportError:
+                html_theme = "sphinx_rtd_theme"
+
+        if html_theme == "sphinx_rtd_theme":
+            # Add color-specific RTD normal mode
+            html_css_files.append("theme_rtd_colors.css")
+
+        html_theme_options = {
+            "navigation_depth": -1,
+        }
+
+    except ImportError:
+        html_theme = "alabaster"
+
+if "DOCS_CSS" in os.environ:
+    css = os.environ["DOCS_CSS"].split(" ")
+
+    for l in css:
+        html_css_files.append(l)
+
+if html_theme == "alabaster":
+    html_theme_options = {
+        "description": get_cline_version(),
+        "page_width": "65em",
+        "sidebar_width": "15em",
+        "fixed_sidebar": "true",
+        "font_size": "inherit",
+        "font_family": "serif",
+    }
+
+sys.stderr.write("Using %s theme\n" % html_theme)
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ["sphinx-static"]
+
+# If true, Docutils "smart quotes" will be used to convert quotes and dashes
+# to typographically correct entities.  However, conversion of "--" to "—"
+# is not always what we want, so enable only quotes.
+smartquotes_action = "q"
+
+# Custom sidebar templates, maps document names to template names.
+# Note that the RTD theme ignores this
+html_sidebars = {"**": ["searchbox.html",
+                        "kernel-toc.html",
+                        "sourcelink.html"]}
+
+# about.html is available for alabaster theme. Add it at the front.
+if html_theme == "alabaster":
+    html_sidebars["**"].insert(0, "about.html")
+
+# The name of an image file (relative to this directory) to place at the top
+# of the sidebar.
+html_logo = "images/logo.svg"
+html_favicon = "images/logo.svg"
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = "TheLinuxKerneldoc"
+
+# -- Options for LaTeX output ---------------------------------------------
+
+latex_elements = {
+    # The paper size ('letterpaper' or 'a4paper').
+    "papersize": "a4paper",
+    "passoptionstopackages": dedent(r"""
+        \PassOptionsToPackage{svgnames}{xcolor}
+    """),
+    # The font size ('10pt', '11pt' or '12pt').
+    "pointsize": "11pt",
+    # Needed to generate a .ind file
+    "printindex": r"\footnotesize\raggedright\printindex",
+    # Latex figure (float) alignment
+    # 'figure_align': 'htbp',
+    # Don't mangle with UTF-8 chars
+    "fontenc": "",
+    "inputenc": "",
+    "utf8extra": "",
+    # Set document margins
+    "sphinxsetup": dedent(r"""
+        hmargin=0.5in, vmargin=1in,
+        parsedliteralwraps=true,
+        verbatimhintsturnover=false,
+    """),
+    #
+    # Some of our authors are fond of deep nesting; tell latex to
+    # cope.
+    #
+    "maxlistdepth": "10",
+    # For CJK One-half spacing, need to be in front of hyperref
+    "extrapackages": r"\usepackage{setspace}",
+    "fontpkg": dedent(r"""
+        \usepackage{fontspec}
+        \setmainfont{DejaVu Serif}
+        \setsansfont{DejaVu Sans}
+        \setmonofont{DejaVu Sans Mono}
+        \newfontfamily\headingfont{DejaVu Serif}
+    """),
+    "preamble": dedent(r"""
+        % Load kerneldoc specific LaTeX settings
+        \input{kerneldoc-preamble.sty}
+    """)
+}
+
+# This will be filled up by config-inited event
+latex_documents = []
+
+# The name of an image file (relative to this directory) to place at the top of
+# the title page.
+# latex_logo = None
+
+# For "manual" documents, if this is true, then toplevel headings are parts,
+# not chapters.
+# latex_use_parts = False
+
+# If true, show page references after internal links.
+# latex_show_pagerefs = False
+
+# If true, show URL addresses after external links.
+# latex_show_urls = False
+
+# Documents to append as an appendix to all manuals.
+# latex_appendices = []
+
+# If false, no module index is generated.
+# latex_domain_indices = True
+
+# Additional LaTeX stuff to be copied to build directory
+latex_additional_files = [
+    "sphinx/kerneldoc-preamble.sty",
+]
+
+
+# -- Options for manual page output ---------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    (master_doc, "thelinuxkernel", "The Linux Kernel Documentation", [author], 1)
+]
+
+# If true, show URL addresses after external links.
+# man_show_urls = False
+
+
+# -- Options for Texinfo output -------------------------------------------
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+#  dir menu entry, description, category)
+texinfo_documents = [(
+        master_doc,
+        "TheLinuxKernel",
+        "The Linux Kernel Documentation",
+        author,
+        "TheLinuxKernel",
+        "One line description of project.",
+        "Miscellaneous",
+    ),]
+
+# -- Options for Epub output ----------------------------------------------
+
+# Bibliographic Dublin Core info.
+epub_title = project
+epub_author = author
+epub_publisher = author
+epub_copyright = copyright
+
+# A list of files that should not be packed into the epub file.
+epub_exclude_files = ["search.html"]
+
+# =======
+# rst2pdf
+#
+# Grouping the document tree into PDF files. List of tuples
+# (source start file, target name, title, author, options).
+#
+# See the Sphinx chapter of https://ralsina.me/static/manual.pdf
+#
+# FIXME: Do not add the index file here; the result will be too big. Adding
+# multiple PDF files here actually tries to get the cross-referencing right
+# *between* PDF files.
+pdf_documents = [
+    ("kernel-documentation", "Kernel", "Kernel", "J. Random Bozo"),
+]
+
+kerneldoc_srctree = ".."
+
+# Add index link at the end of the root document for SPHINXDIRS builds.
+def add_subproject_index(app, docname, content):
+    # Only care about root documents
+    if docname != master_doc:
+        return
+
+    # Add the index link at the root of translations, but not at the root of
+    # individual translations. They have their own language specific links.
+    rel = os.path.relpath(app.srcdir, start=kern_doc_dir).split('/')
+    if rel[0] == 'translations' and len(rel) > 1:
+        return
+
+    # Only add the link for SPHINXDIRS HTML builds
+    if not app.builder.tags.has('subproject') or not app.builder.tags.has('html'):
+        return
+
+    # The include directive needs a relative path from the srcdir
+    rel = os.path.relpath(os.path.join(kern_doc_dir, 'sphinx-includes/subproject-index.rst'),
+                          start=app.srcdir)
+
+    content[0] += f'\n.. include:: {rel}\n\n'
+
+def setup(app):
+    """Patterns need to be updated at init time on older Sphinx versions"""
+
+    app.connect('config-inited', config_init)
+    app.connect('source-read', add_subproject_index)