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 --- fs/init.c | 218 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 218 insertions(+) create mode 100644 fs/init.c (limited to 'fs/init.c') diff --git a/fs/init.c b/fs/init.c new file mode 100644 index 000000000..33e312d74 --- /dev/null +++ b/fs/init.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Routines that mimic syscalls, but don't use the user address space or file + * descriptors. Only for init/ and related early init code. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +int __init init_pivot_root(const char *new_root, const char *put_old) +{ + struct path new_path __free(path_put) = {}; + struct path old_path __free(path_put) = {}; + int ret; + + ret = kern_path(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &new_path); + if (ret) + return ret; + + ret = kern_path(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_path); + if (ret) + return ret; + + return path_pivot_root(&new_path, &old_path); +} + +int __init init_mount(const char *dev_name, const char *dir_name, + const char *type_page, unsigned long flags, void *data_page) +{ + struct path path; + int ret; + + ret = kern_path(dir_name, LOOKUP_FOLLOW, &path); + if (ret) + return ret; + ret = path_mount(dev_name, &path, type_page, flags, data_page); + path_put(&path); + return ret; +} + +int __init init_umount(const char *name, int flags) +{ + int lookup_flags = LOOKUP_MOUNTPOINT; + struct path path; + int ret; + + if (!(flags & UMOUNT_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + ret = kern_path(name, lookup_flags, &path); + if (ret) + return ret; + return path_umount(&path, flags); +} + +int __init init_chdir(const char *filename) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); + if (error) + return error; + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); + if (!error) + set_fs_pwd(current->fs, &path); + path_put(&path); + return error; +} + +int __init init_chroot(const char *filename) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); + if (error) + return error; + error = path_permission(&path, MAY_EXEC | MAY_CHDIR); + if (error) + goto dput_and_out; + error = -EPERM; + if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT)) + goto dput_and_out; + error = security_path_chroot(&path); + if (error) + goto dput_and_out; + set_fs_root(current->fs, &path); +dput_and_out: + path_put(&path); + return error; +} + +int __init init_chown(const char *filename, uid_t user, gid_t group, int flags) +{ + int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; + struct path path; + int error; + + error = kern_path(filename, lookup_flags, &path); + if (error) + return error; + error = mnt_want_write(path.mnt); + if (!error) { + error = chown_common(&path, user, group); + mnt_drop_write(path.mnt); + } + path_put(&path); + return error; +} + +int __init init_chmod(const char *filename, umode_t mode) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW, &path); + if (error) + return error; + error = chmod_common(&path, mode); + path_put(&path); + return error; +} + +int __init init_eaccess(const char *filename) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW, &path); + if (error) + return error; + error = path_permission(&path, MAY_ACCESS); + path_put(&path); + return error; +} + +int __init init_stat(const char *filename, struct kstat *stat, int flags) +{ + int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; + struct path path; + int error; + + error = kern_path(filename, lookup_flags, &path); + if (error) + return error; + error = vfs_getattr(&path, stat, STATX_BASIC_STATS, + flags | AT_NO_AUTOMOUNT); + path_put(&path); + return error; +} + +int __init init_mknod(const char *filename, umode_t mode, unsigned int dev) +{ + CLASS(filename_kernel, name)(filename); + return filename_mknodat(AT_FDCWD, name, mode, dev); +} + +int __init init_link(const char *oldname, const char *newname) +{ + CLASS(filename_kernel, old)(oldname); + CLASS(filename_kernel, new)(newname); + return filename_linkat(AT_FDCWD, old, AT_FDCWD, new, 0); +} + +int __init init_symlink(const char *oldname, const char *newname) +{ + CLASS(filename_kernel, old)(oldname); + CLASS(filename_kernel, new)(newname); + return filename_symlinkat(old, AT_FDCWD, new); +} + +int __init init_unlink(const char *pathname) +{ + CLASS(filename_kernel, name)(pathname); + return filename_unlinkat(AT_FDCWD, name); +} + +int __init init_mkdir(const char *pathname, umode_t mode) +{ + CLASS(filename_kernel, name)(pathname); + return filename_mkdirat(AT_FDCWD, name, mode); +} + +int __init init_rmdir(const char *pathname) +{ + CLASS(filename_kernel, name)(pathname); + return filename_rmdir(AT_FDCWD, name); +} + +int __init init_utimes(char *filename, struct timespec64 *ts) +{ + struct path path; + int error; + + error = kern_path(filename, 0, &path); + if (error) + return error; + error = vfs_utimes(&path, ts); + path_put(&path); + return error; +} + +int __init init_dup(struct file *file) +{ + int fd; + + fd = get_unused_fd_flags(0); + if (fd < 0) + return fd; + fd_install(fd, get_file(file)); + return 0; +} -- cgit v1.3.1