ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 180 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
new file mode 100644
index 000000000..a68873880
--- /dev/null
+++ b/tools/perf/Documentation/perf-annotate.txt
@@ -0,0 +1,180 @@
+perf-annotate(1)
+================
+
+NAME
+----
+perf-annotate - Read perf.data (created by perf record) and display annotated code
+
+SYNOPSIS
+--------
+[verse]
+'perf annotate' [-i <file> | --input=file] [symbol_name]
+
+DESCRIPTION
+-----------
+This command reads the input file and displays an annotated version of the
+code. If the object file has debug symbols then the source code will be
+displayed alongside assembly code.
+
+If there is no debug info in the object, then annotated assembly is displayed.
+
+OPTIONS
+-------
+-i::
+--input=<file>::
+        Input file name. (default: perf.data unless stdin is a fifo)
+
+-d::
+--dsos=<dso[,dso...]>::
+        Only consider symbols in these dsos.
+-s::
+--symbol=<symbol>::
+        Symbol to annotate.
+
+-f::
+--force::
+        Don't do ownership validation.
+
+-v::
+--verbose::
+        Be more verbose. (Show symbol address, etc)
+
+-q::
+--quiet::
+	Do not show any warnings or messages.  (Suppress -v)
+
+-n::
+--show-nr-samples::
+	Show the number of samples for each symbol
+
+-D::
+--dump-raw-trace::
+        Dump raw trace in ASCII.
+
+-k::
+--vmlinux=<file>::
+        vmlinux pathname.
+
+--ignore-vmlinux::
+	Ignore vmlinux files.
+
+--itrace::
+	Options for decoding instruction tracing data. The options are:
+
+include::itrace.txt[]
+
+	To disable decoding entirely, use --no-itrace.
+
+-m::
+--modules::
+        Load module symbols. WARNING: use only with -k and LIVE kernel.
+
+-l::
+--print-line::
+        Print matching source lines (may be slow).
+
+-P::
+--full-paths::
+        Don't shorten the displayed pathnames.
+
+--stdio:: Use the stdio interface.
+
+--stdio2:: Use the stdio2 interface, non-interactive, uses the TUI formatting.
+
+--stdio-color=<mode>::
+	'always', 'never' or 'auto', allowing configuring color output
+	via the command line, in addition to via "color.ui" .perfconfig.
+	Use '--stdio-color always' to generate color even when redirecting
+	to a pipe or file. Using just '--stdio-color' is equivalent to
+	using 'always'.
+
+--tui:: Use the TUI interface. Use of --tui requires a tty, if one is not
+	present, as when piping to other commands, the stdio interface is
+	used. This interfaces starts by centering on the line with more
+	samples, TAB/UNTAB cycles through the lines with more samples.
+
+--gtk:: Use the GTK interface.
+
+-C::
+--cpu=<cpu>:: Only report samples for the list of CPUs provided. Multiple CPUs can
+	be provided as a comma-separated list with no space: 0,1. Ranges of
+	CPUs are specified with -: 0-2. Default is to report samples on all
+	CPUs.
+
+--asm-raw::
+	Show raw instruction encoding of assembly instructions.
+
+--show-total-period:: Show a column with the sum of periods.
+
+--source::
+	Interleave source code with assembly code. Enabled by default,
+	disable with --no-source.
+
+--symfs=<directory[,layout]>::
+        Look for files with symbols relative to this directory. The optional
+        layout can be 'hierarchy' (default, matches full path) or 'flat'
+        (only matches base name). This is useful when debug files are stored
+        in a flat directory structure.
+
+-M::
+--disassembler-style=:: Set disassembler style for objdump.
+
+--addr2line=<path>::
+        Path to addr2line binary.
+
+--objdump=<path>::
+        Path to objdump binary.
+
+--prefix=PREFIX::
+--prefix-strip=N::
+	Remove first N entries from source file path names in executables
+	and add PREFIX. This allows to display source code compiled on systems
+	with different file system layout.
+
+--skip-missing::
+	Skip symbols that cannot be annotated.
+
+--group::
+	Show event group information together
+
+--demangle::
+	Demangle symbol names to human readable form. It's enabled by default,
+	disable with --no-demangle.
+
+--demangle-kernel::
+	Demangle kernel symbol names to human readable form (for C++ kernels).
+
+--percent-type::
+	Set annotation percent type from following choices:
+	  global-period, local-period, global-hits, local-hits
+
+	The local/global keywords set if the percentage is computed
+	in the scope of the function (local) or the whole data (global).
+	The period/hits keywords set the base the percentage is computed
+	on - the samples period or the number of samples (hits).
+
+--percent-limit::
+	Do not show functions which have an overhead under that percent on
+	stdio or stdio2 (Default: 0).  Note that this is about selection of
+	functions to display, not about lines within the function.
+
+--data-type[=TYPE_NAME]::
+	Display data type annotation instead of code.  It infers data type of
+	samples (if they are memory accessing instructions) using DWARF debug
+	information.  It can take an optional argument of data type name.  In
+	that case it'd show annotation for the type only, otherwise it'd show
+	all data types it finds.
+
+--type-stat::
+	Show stats for the data type annotation.
+
+--skip-empty::
+	Do not display empty (or dummy) events.
+
+--code-with-type::
+	Show data type info in code annotation (for memory instructions only).
+
+
+SEE ALSO
+--------
+linkperf:perf-record[1], linkperf:perf-report[1]