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 --- .../dummy-plugin-dir/include/plugin-version.h | 0 scripts/dummy-tools/gcc | 116 +++++++++++++++++++++ scripts/dummy-tools/ld | 30 ++++++ scripts/dummy-tools/nm | 1 + scripts/dummy-tools/objcopy | 1 + scripts/dummy-tools/pahole | 4 + scripts/dummy-tools/python3 | 4 + 7 files changed, 156 insertions(+) create mode 100644 scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h create mode 100755 scripts/dummy-tools/gcc create mode 100755 scripts/dummy-tools/ld create mode 120000 scripts/dummy-tools/nm create mode 120000 scripts/dummy-tools/objcopy create mode 100755 scripts/dummy-tools/pahole create mode 100755 scripts/dummy-tools/python3 (limited to 'scripts/dummy-tools') diff --git a/scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h b/scripts/dummy-tools/dummy-plugin-dir/include/plugin-version.h new file mode 100644 index 000000000..e69de29bb diff --git a/scripts/dummy-tools/gcc b/scripts/dummy-tools/gcc new file mode 100755 index 000000000..e6c41427c --- /dev/null +++ b/scripts/dummy-tools/gcc @@ -0,0 +1,116 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +# +# Staring v4.18, Kconfig evaluates compiler capabilities, and hides CONFIG +# options your compiler does not support. This works well if you configure and +# build the kernel on the same host machine. +# +# It is inconvenient if you prepare the .config that is carried to a different +# build environment (typically this happens when you package the kernel for +# distros) because using a different compiler potentially produces different +# CONFIG options than the real build environment. So, you probably want to make +# as many options visible as possible. In other words, you need to create a +# super-set of CONFIG options that cover any build environment. If some of the +# CONFIG options turned out to be unsupported on the build machine, they are +# automatically disabled by the nature of Kconfig. +# +# However, it is not feasible to get a full-featured compiler for every arch. +# Hence these dummy toolchains to make all compiler tests pass. +# +# Usage: +# +# From the top directory of the source tree, run +# +# $ make CROSS_COMPILE=scripts/dummy-tools/ oldconfig +# +# Most of compiler features are tested by cc-option, which simply checks the +# exit code of $(CC). This script does nothing and just exits with 0 in most +# cases. So, $(cc-option, ...) is evaluated as 'y'. +# +# This scripts caters to more checks; handle --version and pre-process __GNUC__ +# etc. to pretend to be GCC, and also do right things to satisfy some scripts. + +# Check if the first parameter appears in the rest. Succeeds if found. +# This helper is useful if a particular option was passed to this script. +# Typically used like this: +# arg_contain "$@" +arg_contain () +{ + search="$1" + shift + + while [ $# -gt 0 ] + do + if [ "$search" = "$1" ]; then + return 0 + fi + shift + done + + return 1 +} + +# To set CONFIG_CC_IS_GCC=y +if arg_contain --version "$@"; then + echo "gcc (scripts/dummy-tools/gcc)" + exit 0 +fi + +if arg_contain -E "$@"; then + # For scripts/cc-version.sh; This emulates GCC 20.0.0 + if arg_contain - "$@"; then + sed -n '/^GCC/{s/__GNUC__/20/; s/__GNUC_MINOR__/0/; s/__GNUC_PATCHLEVEL__/0/; p;}; s/__LONG_DOUBLE_128__/1/ p' + exit 0 + else + echo "no input files" >&2 + exit 1 + fi +fi + +# To set CONFIG_AS_IS_GNU +if arg_contain -Wa,--version "$@"; then + echo "GNU assembler (scripts/dummy-tools) 2.50" + exit 0 +fi + +if arg_contain -S "$@"; then + # For scripts/gcc-x86-*-has-stack-protector.sh + if arg_contain -fstack-protector "$@"; then + if arg_contain -mstack-protector-guard-reg=fs "$@"; then + echo "%fs" + else + echo "%gs" + fi + exit 0 + fi + + # For arch/powerpc/tools/gcc-check-mprofile-kernel.sh + if arg_contain -m64 "$@" && arg_contain -mprofile-kernel "$@"; then + if ! test -t 0 && ! grep -q notrace; then + echo "_mcount" + fi + exit 0 + fi + + # For arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh + if arg_contain -m64 "$@" && arg_contain -fpatchable-function-entry=2 "$@"; then + echo "func:" + echo ".section __patchable_function_entries" + echo ".localentry" + echo " nop" + echo " nop" + exit 0 + fi +fi + +# To set GCC_PLUGINS +if arg_contain -print-file-name=plugin "$@"; then + # Use $0 to find the in-tree dummy directory + echo "$(dirname "$(readlink -f "$0")")/dummy-plugin-dir" + exit 0 +fi + +# inverted return value +if arg_contain -D__SIZEOF_INT128__=0 "$@"; then + exit 1 +fi diff --git a/scripts/dummy-tools/ld b/scripts/dummy-tools/ld new file mode 100755 index 000000000..f68233050 --- /dev/null +++ b/scripts/dummy-tools/ld @@ -0,0 +1,30 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +# Dummy script that always succeeds. + +# Check if the first parameter appears in the rest. Succeeds if found. +# This helper is useful if a particular option was passed to this script. +# Typically used like this: +# arg_contain "$@" +arg_contain () +{ + search="$1" + shift + + while [ $# -gt 0 ] + do + if [ "$search" = "$1" ]; then + return 0 + fi + shift + done + + return 1 +} + +if arg_contain --version "$@" || arg_contain -v "$@"; then + progname=$(basename $0) + echo "GNU $progname (scripts/dummy-tools/$progname) 2.50" + exit 0 +fi diff --git a/scripts/dummy-tools/nm b/scripts/dummy-tools/nm new file mode 120000 index 000000000..c0648b38d --- /dev/null +++ b/scripts/dummy-tools/nm @@ -0,0 +1 @@ +ld \ No newline at end of file diff --git a/scripts/dummy-tools/objcopy b/scripts/dummy-tools/objcopy new file mode 120000 index 000000000..c0648b38d --- /dev/null +++ b/scripts/dummy-tools/objcopy @@ -0,0 +1 @@ +ld \ No newline at end of file diff --git a/scripts/dummy-tools/pahole b/scripts/dummy-tools/pahole new file mode 100755 index 000000000..53501a36f --- /dev/null +++ b/scripts/dummy-tools/pahole @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +echo v99.99 diff --git a/scripts/dummy-tools/python3 b/scripts/dummy-tools/python3 new file mode 100755 index 000000000..24c558486 --- /dev/null +++ b/scripts/dummy-tools/python3 @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +true -- cgit v1.3.1