From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- lib/build_OID_registry | 218 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 218 insertions(+) create mode 100755 lib/build_OID_registry (limited to 'lib/build_OID_registry') diff --git a/lib/build_OID_registry b/lib/build_OID_registry new file mode 100755 index 000000000..30493ac19 --- /dev/null +++ b/lib/build_OID_registry @@ -0,0 +1,218 @@ +#!/usr/bin/perl -w +# SPDX-License-Identifier: GPL-2.0-or-later +# +# Build a static ASN.1 Object Identified (OID) registry +# +# Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. +# Written by David Howells (dhowells@redhat.com) +# + +use strict; +use Cwd qw(abs_path); + +my @names = (); +my @oids = (); + +if ($#ARGV != 1) { + print STDERR "Format: ", $0, " \n"; + exit(2); +} + +my $abs_srctree = abs_path($ENV{'srctree'}); + +# +# Open the file to read from +# +open IN_FILE, "<$ARGV[0]" || die; +while () { + chomp; + if (m!\s+OID_([a-zA-z][a-zA-Z0-9_]+),\s+/[*]\s+([012][.0-9]*)\s+[*]/!) { + push @names, $1; + push @oids, $2; + } +} +close IN_FILE || die; + +# +# Open the files to write into +# +open C_FILE, ">$ARGV[1]" or die; +print C_FILE "/*\n"; +my $scriptname = $0; +$scriptname =~ s#^\Q$abs_srctree/\E##; +print C_FILE " * Automatically generated by ", $scriptname, ". Do not edit\n"; +print C_FILE " */\n"; + +# +# Split the data up into separate lists and also determine the lengths of the +# encoded data arrays. +# +my @indices = (); +my @lengths = (); +my $total_length = 0; + +for (my $i = 0; $i <= $#names; $i++) { + my $name = $names[$i]; + my $oid = $oids[$i]; + + my @components = split(/[.]/, $oid); + + # Determine the encoded length of this OID + my $size = $#components; + for (my $loop = 2; $loop <= $#components; $loop++) { + $ENV{'BC_LINE_LENGTH'} = "0"; + my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`; + chomp($c); + + # We will base128 encode the number + my $tmp = length($c) - 1; + $tmp = int($tmp / 7); + $size += $tmp; + } + push @lengths, $size; + push @indices, $total_length; + $total_length += $size; +} + +# +# Emit the look-up-by-OID index table +# +print C_FILE "\n"; +if ($total_length <= 255) { + print C_FILE "static const unsigned char oid_index[OID__NR + 1] = {\n"; +} else { + print C_FILE "static const unsigned short oid_index[OID__NR + 1] = {\n"; +} +for (my $i = 0; $i <= $#names; $i++) { + print C_FILE "\t[OID_", $names[$i], "] = ", $indices[$i], ",\n" +} +print C_FILE "\t[OID__NR] = ", $total_length, "\n"; +print C_FILE "};\n"; + +# +# Encode the OIDs +# +my @encoded_oids = (); + +for (my $i = 0; $i <= $#names; $i++) { + my @octets = (); + + my @components = split(/[.]/, $oids[$i]); + + push @octets, $components[0] * 40 + $components[1]; + + for (my $loop = 2; $loop <= $#components; $loop++) { + # get the base 2 representation of the component + $ENV{'BC_LINE_LENGTH'} = "0"; + my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`; + chomp($c); + + my $tmp = length($c) - 1; + $tmp = int($tmp / 7); + + # zero pad upto length multiple of 7 + $c = substr("0000000", 0, ($tmp + 1) * 7 - length($c)).$c; + + # Base128 encode the number + for (my $j = 0; $j < $tmp; $j++) { + my $b = oct("0b".substr($c, $j * 7, 7)); + + push @octets, $b | 0x80; + } + push @octets, oct("0b".substr($c, $tmp * 7, 7)); + } + + push @encoded_oids, \@octets; +} + +# +# Create a hash value for each OID +# +my @hash_values = (); +for (my $i = 0; $i <= $#names; $i++) { + my @octets = @{$encoded_oids[$i]}; + + my $hash = $#octets; + foreach (@octets) { + $hash += $_ * 33; + } + + $hash = ($hash >> 24) ^ ($hash >> 16) ^ ($hash >> 8) ^ ($hash); + + push @hash_values, $hash & 0xff; +} + +# +# Emit the OID data +# +print C_FILE "\n"; +print C_FILE "static const unsigned char oid_data[", $total_length, "] = {\n"; +for (my $i = 0; $i <= $#names; $i++) { + my @octets = @{$encoded_oids[$i]}; + print C_FILE "\t"; + print C_FILE $_, ", " foreach (@octets); + print C_FILE "\t// ", $names[$i]; + print C_FILE "\n"; +} +print C_FILE "};\n"; + +# +# Build the search index table (ordered by length then hash then content) +# +my @index_table = ( 0 .. $#names ); + +@index_table = sort { + my @octets_a = @{$encoded_oids[$a]}; + my @octets_b = @{$encoded_oids[$b]}; + + return $hash_values[$a] <=> $hash_values[$b] + if ($hash_values[$a] != $hash_values[$b]); + return $#octets_a <=> $#octets_b + if ($#octets_a != $#octets_b); + for (my $i = $#octets_a; $i >= 0; $i--) { + return $octets_a[$i] <=> $octets_b[$i] + if ($octets_a[$i] != $octets_b[$i]); + } + return 0; + +} @index_table; + +# +# Emit the search index and hash value table +# +print C_FILE "\n"; +print C_FILE "static const struct {\n"; +print C_FILE "\tunsigned char hash;\n"; +if ($#names <= 255) { + print C_FILE "\tenum OID oid : 8;\n"; +} else { + print C_FILE "\tenum OID oid : 16;\n"; +} +print C_FILE "} oid_search_table[OID__NR] = {\n"; +for (my $i = 0; $i <= $#names; $i++) { + my @octets = @{$encoded_oids[$index_table[$i]]}; + printf(C_FILE "\t[%3u] = { %3u, OID_%-35s }, // ", + $i, + $hash_values[$index_table[$i]], + $names[$index_table[$i]]); + printf C_FILE "%02x", $_ foreach (@octets); + print C_FILE "\n"; +} +print C_FILE "};\n"; + +# +# Emit the OID debugging name table +# +#print C_FILE "\n"; +#print C_FILE "const char *const oid_name_table[OID__NR + 1] = {\n"; +# +#for (my $i = 0; $i <= $#names; $i++) { +# print C_FILE "\t\"", $names[$i], "\",\n" +#} +#print C_FILE "\t\"Unknown-OID\"\n"; +#print C_FILE "};\n"; + +# +# Polish off +# +close C_FILE or die; -- cgit v1.3.1