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/statfs.c | 405 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 405 insertions(+) create mode 100644 fs/statfs.c (limited to 'fs/statfs.c') diff --git a/fs/statfs.c b/fs/statfs.c new file mode 100644 index 000000000..377bcef7a --- /dev/null +++ b/fs/statfs.c @@ -0,0 +1,405 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int flags_by_mnt(int mnt_flags) +{ + int flags = 0; + + if (mnt_flags & MNT_READONLY) + flags |= ST_RDONLY; + if (mnt_flags & MNT_NOSUID) + flags |= ST_NOSUID; + if (mnt_flags & MNT_NODEV) + flags |= ST_NODEV; + if (mnt_flags & MNT_NOEXEC) + flags |= ST_NOEXEC; + if (mnt_flags & MNT_NOATIME) + flags |= ST_NOATIME; + if (mnt_flags & MNT_NODIRATIME) + flags |= ST_NODIRATIME; + if (mnt_flags & MNT_RELATIME) + flags |= ST_RELATIME; + if (mnt_flags & MNT_NOSYMFOLLOW) + flags |= ST_NOSYMFOLLOW; + return flags; +} + +static int flags_by_sb(int s_flags) +{ + int flags = 0; + if (s_flags & SB_SYNCHRONOUS) + flags |= ST_SYNCHRONOUS; + if (s_flags & SB_MANDLOCK) + flags |= ST_MANDLOCK; + if (s_flags & SB_RDONLY) + flags |= ST_RDONLY; + return flags; +} + +static int calculate_f_flags(struct vfsmount *mnt) +{ + return ST_VALID | flags_by_mnt(mnt->mnt_flags) | + flags_by_sb(mnt->mnt_sb->s_flags); +} + +static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf) +{ + int retval; + + if (!dentry->d_sb->s_op->statfs) + return -ENOSYS; + + memset(buf, 0, sizeof(*buf)); + retval = security_sb_statfs(dentry); + if (retval) + return retval; + retval = dentry->d_sb->s_op->statfs(dentry, buf); + if (retval == 0 && buf->f_frsize == 0) + buf->f_frsize = buf->f_bsize; + return retval; +} + +int vfs_get_fsid(struct dentry *dentry, __kernel_fsid_t *fsid) +{ + struct kstatfs st; + int error; + + error = statfs_by_dentry(dentry, &st); + if (error) + return error; + + *fsid = st.f_fsid; + return 0; +} +EXPORT_SYMBOL(vfs_get_fsid); + +int vfs_statfs(const struct path *path, struct kstatfs *buf) +{ + int error; + + error = statfs_by_dentry(path->dentry, buf); + if (!error) + buf->f_flags = calculate_f_flags(path->mnt); + return error; +} +EXPORT_SYMBOL(vfs_statfs); + +int user_statfs(const char __user *pathname, struct kstatfs *st) +{ + struct path path; + int error; + unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT; + CLASS(filename, name)(pathname); +retry: + error = filename_lookup(AT_FDCWD, name, lookup_flags, &path, NULL); + if (!error) { + error = vfs_statfs(&path, st); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } + } + return error; +} + +int fd_statfs(int fd, struct kstatfs *st) +{ + CLASS(fd_raw, f)(fd); + + if (fd_empty(f)) + return -EBADF; + return vfs_statfs(&fd_file(f)->f_path, st); +} + +static int do_statfs_native(struct kstatfs *st, struct statfs __user *p) +{ + struct statfs buf; + + if (sizeof(buf) == sizeof(*st)) + memcpy(&buf, st, sizeof(*st)); + else { + memset(&buf, 0, sizeof(buf)); + if (sizeof buf.f_blocks == 4) { + if ((st->f_blocks | st->f_bfree | st->f_bavail | + st->f_bsize | st->f_frsize) & + 0xffffffff00000000ULL) + return -EOVERFLOW; + /* + * f_files and f_ffree may be -1; it's okay to stuff + * that into 32 bits + */ + if (st->f_files != -1 && + (st->f_files & 0xffffffff00000000ULL)) + return -EOVERFLOW; + if (st->f_ffree != -1 && + (st->f_ffree & 0xffffffff00000000ULL)) + return -EOVERFLOW; + } + + buf.f_type = st->f_type; + buf.f_bsize = st->f_bsize; + buf.f_blocks = st->f_blocks; + buf.f_bfree = st->f_bfree; + buf.f_bavail = st->f_bavail; + buf.f_files = st->f_files; + buf.f_ffree = st->f_ffree; + buf.f_fsid = st->f_fsid; + buf.f_namelen = st->f_namelen; + buf.f_frsize = st->f_frsize; + buf.f_flags = st->f_flags; + } + if (copy_to_user(p, &buf, sizeof(buf))) + return -EFAULT; + return 0; +} + +static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) +{ + struct statfs64 buf; + if (sizeof(buf) == sizeof(*st)) + memcpy(&buf, st, sizeof(*st)); + else { + memset(&buf, 0, sizeof(buf)); + buf.f_type = st->f_type; + buf.f_bsize = st->f_bsize; + buf.f_blocks = st->f_blocks; + buf.f_bfree = st->f_bfree; + buf.f_bavail = st->f_bavail; + buf.f_files = st->f_files; + buf.f_ffree = st->f_ffree; + buf.f_fsid = st->f_fsid; + buf.f_namelen = st->f_namelen; + buf.f_frsize = st->f_frsize; + buf.f_flags = st->f_flags; + } + if (copy_to_user(p, &buf, sizeof(buf))) + return -EFAULT; + return 0; +} + +SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) +{ + struct kstatfs st; + int error = user_statfs(pathname, &st); + if (!error) + error = do_statfs_native(&st, buf); + return error; +} + +SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) +{ + struct kstatfs st; + int error; + if (sz != sizeof(*buf)) + return -EINVAL; + error = user_statfs(pathname, &st); + if (!error) + error = do_statfs64(&st, buf); + return error; +} + +SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) +{ + struct kstatfs st; + int error = fd_statfs(fd, &st); + if (!error) + error = do_statfs_native(&st, buf); + return error; +} + +SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) +{ + struct kstatfs st; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = fd_statfs(fd, &st); + if (!error) + error = do_statfs64(&st, buf); + return error; +} + +static int vfs_ustat(dev_t dev, struct kstatfs *sbuf) +{ + struct super_block *s = user_get_super(dev, false); + int err; + if (!s) + return -EINVAL; + + err = statfs_by_dentry(s->s_root, sbuf); + drop_super(s); + return err; +} + +SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) +{ + struct ustat tmp; + struct kstatfs sbuf; + int err = vfs_ustat(new_decode_dev(dev), &sbuf); + if (err) + return err; + + memset(&tmp,0,sizeof(struct ustat)); + tmp.f_tfree = sbuf.f_bfree; + if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE)) + tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX); + else + tmp.f_tinode = sbuf.f_ffree; + + return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0; +} + +#ifdef CONFIG_COMPAT +static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf) +{ + struct compat_statfs buf; + if (sizeof ubuf->f_blocks == 4) { + if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail | + kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) + return -EOVERFLOW; + /* f_files and f_ffree may be -1; it's okay + * to stuff that into 32 bits */ + if (kbuf->f_files != 0xffffffffffffffffULL + && (kbuf->f_files & 0xffffffff00000000ULL)) + return -EOVERFLOW; + if (kbuf->f_ffree != 0xffffffffffffffffULL + && (kbuf->f_ffree & 0xffffffff00000000ULL)) + return -EOVERFLOW; + } + memset(&buf, 0, sizeof(struct compat_statfs)); + buf.f_type = kbuf->f_type; + buf.f_bsize = kbuf->f_bsize; + buf.f_blocks = kbuf->f_blocks; + buf.f_bfree = kbuf->f_bfree; + buf.f_bavail = kbuf->f_bavail; + buf.f_files = kbuf->f_files; + buf.f_ffree = kbuf->f_ffree; + buf.f_namelen = kbuf->f_namelen; + buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; + buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; + buf.f_frsize = kbuf->f_frsize; + buf.f_flags = kbuf->f_flags; + if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs))) + return -EFAULT; + return 0; +} + +/* + * The following statfs calls are copies of code from fs/statfs.c and + * should be checked against those from time to time + */ +COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf) +{ + struct kstatfs tmp; + int error = user_statfs(pathname, &tmp); + if (!error) + error = put_compat_statfs(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf) +{ + struct kstatfs tmp; + int error = fd_statfs(fd, &tmp); + if (!error) + error = put_compat_statfs(buf, &tmp); + return error; +} + +static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf) +{ + struct compat_statfs64 buf; + + if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) + return -EOVERFLOW; + + memset(&buf, 0, sizeof(struct compat_statfs64)); + buf.f_type = kbuf->f_type; + buf.f_bsize = kbuf->f_bsize; + buf.f_blocks = kbuf->f_blocks; + buf.f_bfree = kbuf->f_bfree; + buf.f_bavail = kbuf->f_bavail; + buf.f_files = kbuf->f_files; + buf.f_ffree = kbuf->f_ffree; + buf.f_namelen = kbuf->f_namelen; + buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; + buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; + buf.f_frsize = kbuf->f_frsize; + buf.f_flags = kbuf->f_flags; + if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs64))) + return -EFAULT; + return 0; +} + +int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf) +{ + struct kstatfs tmp; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = user_statfs(pathname, &tmp); + if (!error) + error = put_compat_statfs64(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_statfs64(pathname, sz, buf); +} + +int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf) +{ + struct kstatfs tmp; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = fd_statfs(fd, &tmp); + if (!error) + error = put_compat_statfs64(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_fstatfs64(fd, sz, buf); +} + +/* + * This is a copy of sys_ustat, just dealing with a structure layout. + * Given how simple this syscall is that apporach is more maintainable + * than the various conversion hacks. + */ +COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u) +{ + struct compat_ustat tmp; + struct kstatfs sbuf; + int err = vfs_ustat(new_decode_dev(dev), &sbuf); + if (err) + return err; + + memset(&tmp, 0, sizeof(struct compat_ustat)); + tmp.f_tfree = sbuf.f_bfree; + tmp.f_tinode = sbuf.f_ffree; + if (copy_to_user(u, &tmp, sizeof(struct compat_ustat))) + return -EFAULT; + return 0; +} +#endif -- cgit v1.3.1