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, 318 insertions, 0 deletions

diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
new file mode 100644
index 000000000..1b4fcf760
--- /dev/null
+++ b/fs/hpfs/inode.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hpfs/inode.c
+ *
+ *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
+ *
+ *  inode VFS functions
+ */
+
+#include <linux/slab.h>
+#include <linux/user_namespace.h>
+#include "hpfs_fn.h"
+
+void hpfs_init_inode(struct inode *i)
+{
+	struct super_block *sb = i->i_sb;
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+
+	i->i_uid = hpfs_sb(sb)->sb_uid;
+	i->i_gid = hpfs_sb(sb)->sb_gid;
+	i->i_mode = hpfs_sb(sb)->sb_mode;
+	i->i_size = -1;
+	i->i_blocks = -1;
+	
+	hpfs_inode->i_dno = 0;
+	hpfs_inode->i_n_secs = 0;
+	hpfs_inode->i_file_sec = 0;
+	hpfs_inode->i_disk_sec = 0;
+	hpfs_inode->i_dpos = 0;
+	hpfs_inode->i_dsubdno = 0;
+	hpfs_inode->i_ea_mode = 0;
+	hpfs_inode->i_ea_uid = 0;
+	hpfs_inode->i_ea_gid = 0;
+	hpfs_inode->i_ea_size = 0;
+
+	hpfs_inode->i_rddir_off = NULL;
+	hpfs_inode->i_dirty = 0;
+
+	inode_set_ctime(i, 0, 0);
+	inode_set_mtime(i, 0, 0);
+	inode_set_atime(i, 0, 0);
+}
+
+void hpfs_read_inode(struct inode *i)
+{
+	struct buffer_head *bh;
+	struct fnode *fnode;
+	struct super_block *sb = i->i_sb;
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	void *ea;
+	int ea_size;
+
+	if (!(fnode = hpfs_map_fnode(sb, i->i_ino, &bh))) {
+		/*i->i_mode |= S_IFREG;
+		i->i_mode &= ~0111;
+		i->i_op = &hpfs_file_iops;
+		i->i_fop = &hpfs_file_ops;
+		clear_nlink(i);*/
+		make_bad_inode(i);
+		return;
+	}
+	if (hpfs_sb(i->i_sb)->sb_eas) {
+		if ((ea = hpfs_get_ea(i->i_sb, fnode, "UID", &ea_size))) {
+			if (ea_size == 2) {
+				i_uid_write(i, le16_to_cpu(*(__le16*)ea));
+				hpfs_inode->i_ea_uid = 1;
+			}
+			kfree(ea);
+		}
+		if ((ea = hpfs_get_ea(i->i_sb, fnode, "GID", &ea_size))) {
+			if (ea_size == 2) {
+				i_gid_write(i, le16_to_cpu(*(__le16*)ea));
+				hpfs_inode->i_ea_gid = 1;
+			}
+			kfree(ea);
+		}
+		if ((ea = hpfs_get_ea(i->i_sb, fnode, "SYMLINK", &ea_size))) {
+			kfree(ea);
+			i->i_mode = S_IFLNK | 0777;
+			i->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(i);
+			i->i_data.a_ops = &hpfs_symlink_aops;
+			set_nlink(i, 1);
+			i->i_size = ea_size;
+			i->i_blocks = 1;
+			brelse(bh);
+			return;
+		}
+		if ((ea = hpfs_get_ea(i->i_sb, fnode, "MODE", &ea_size))) {
+			int rdev = 0;
+			umode_t mode = hpfs_sb(sb)->sb_mode;
+			if (ea_size == 2) {
+				mode = le16_to_cpu(*(__le16*)ea);
+				hpfs_inode->i_ea_mode = 1;
+			}
+			kfree(ea);
+			i->i_mode = mode;
+			if (S_ISBLK(mode) || S_ISCHR(mode)) {
+				if ((ea = hpfs_get_ea(i->i_sb, fnode, "DEV", &ea_size))) {
+					if (ea_size == 4)
+						rdev = le32_to_cpu(*(__le32*)ea);
+					kfree(ea);
+				}
+			}
+			if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
+				brelse(bh);
+				set_nlink(i, 1);
+				i->i_size = 0;
+				i->i_blocks = 1;
+				init_special_inode(i, mode,
+					new_decode_dev(rdev));
+				return;
+			}
+		}
+	}
+	if (fnode_is_dir(fnode)) {
+		int n_dnodes, n_subdirs;
+		i->i_mode |= S_IFDIR;
+		i->i_op = &hpfs_dir_iops;
+		i->i_fop = &hpfs_dir_ops;
+		hpfs_inode->i_parent_dir = le32_to_cpu(fnode->up);
+		hpfs_inode->i_dno = le32_to_cpu(fnode->u.external[0].disk_secno);
+		if (hpfs_sb(sb)->sb_chk >= 2) {
+			struct buffer_head *bh0;
+			if (hpfs_map_fnode(sb, hpfs_inode->i_parent_dir, &bh0)) brelse(bh0);
+		}
+		n_dnodes = 0; n_subdirs = 0;
+		hpfs_count_dnodes(i->i_sb, hpfs_inode->i_dno, &n_dnodes, &n_subdirs, NULL);
+		i->i_blocks = 4 * n_dnodes;
+		i->i_size = 2048 * n_dnodes;
+		set_nlink(i, 2 + n_subdirs);
+	} else {
+		i->i_mode |= S_IFREG;
+		if (!hpfs_inode->i_ea_mode) i->i_mode &= ~0111;
+		i->i_op = &hpfs_file_iops;
+		i->i_fop = &hpfs_file_ops;
+		set_nlink(i, 1);
+		i->i_size = le32_to_cpu(fnode->file_size);
+		i->i_blocks = ((i->i_size + 511) >> 9) + 1;
+		i->i_data.a_ops = &hpfs_aops;
+		hpfs_i(i)->mmu_private = i->i_size;
+	}
+	brelse(bh);
+}
+
+static void hpfs_write_inode_ea(struct inode *i, struct fnode *fnode)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	/*if (le32_to_cpu(fnode->acl_size_l) || le16_to_cpu(fnode->acl_size_s)) {
+		   Some unknown structures like ACL may be in fnode,
+		   we'd better not overwrite them
+		hpfs_error(i->i_sb, "fnode %08x has some unknown HPFS386 structures", i->i_ino);
+	} else*/ if (hpfs_sb(i->i_sb)->sb_eas >= 2) {
+		__le32 ea;
+		if (!uid_eq(i->i_uid, hpfs_sb(i->i_sb)->sb_uid) || hpfs_inode->i_ea_uid) {
+			ea = cpu_to_le32(i_uid_read(i));
+			hpfs_set_ea(i, fnode, "UID", (char*)&ea, 2);
+			hpfs_inode->i_ea_uid = 1;
+		}
+		if (!gid_eq(i->i_gid, hpfs_sb(i->i_sb)->sb_gid) || hpfs_inode->i_ea_gid) {
+			ea = cpu_to_le32(i_gid_read(i));
+			hpfs_set_ea(i, fnode, "GID", (char *)&ea, 2);
+			hpfs_inode->i_ea_gid = 1;
+		}
+		if (!S_ISLNK(i->i_mode))
+			if ((i->i_mode != ((hpfs_sb(i->i_sb)->sb_mode & ~(S_ISDIR(i->i_mode) ? 0 : 0111))
+			  | (S_ISDIR(i->i_mode) ? S_IFDIR : S_IFREG))
+			  && i->i_mode != ((hpfs_sb(i->i_sb)->sb_mode & ~(S_ISDIR(i->i_mode) ? 0222 : 0333))
+			  | (S_ISDIR(i->i_mode) ? S_IFDIR : S_IFREG))) || hpfs_inode->i_ea_mode) {
+				ea = cpu_to_le32(i->i_mode);
+				/* sick, but legal */
+				hpfs_set_ea(i, fnode, "MODE", (char *)&ea, 2);
+				hpfs_inode->i_ea_mode = 1;
+			}
+		if (S_ISBLK(i->i_mode) || S_ISCHR(i->i_mode)) {
+			ea = cpu_to_le32(new_encode_dev(i->i_rdev));
+			hpfs_set_ea(i, fnode, "DEV", (char *)&ea, 4);
+		}
+	}
+}
+
+void hpfs_write_inode(struct inode *i)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	struct inode *parent;
+	if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
+	if (hpfs_inode->i_rddir_off && !icount_read_once(i)) {
+		if (*hpfs_inode->i_rddir_off)
+			pr_err("write_inode: some position still there\n");
+		kfree(hpfs_inode->i_rddir_off);
+		hpfs_inode->i_rddir_off = NULL;
+	}
+	if (!i->i_nlink) {
+		return;
+	}
+	parent = iget_locked(i->i_sb, hpfs_inode->i_parent_dir);
+	if (parent) {
+		hpfs_inode->i_dirty = 0;
+		if (inode_state_read_once(parent) & I_NEW) {
+			hpfs_init_inode(parent);
+			hpfs_read_inode(parent);
+			unlock_new_inode(parent);
+		}
+		hpfs_write_inode_nolock(i);
+		iput(parent);
+	}
+}
+
+void hpfs_write_inode_nolock(struct inode *i)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	struct buffer_head *bh;
+	struct fnode *fnode;
+	struct quad_buffer_head qbh;
+	struct hpfs_dirent *de;
+	if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
+	if (!(fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh))) return;
+	if (i->i_ino != hpfs_sb(i->i_sb)->sb_root && i->i_nlink) {
+		if (!(de = map_fnode_dirent(i->i_sb, i->i_ino, fnode, &qbh))) {
+			brelse(bh);
+			return;
+		}
+	} else de = NULL;
+	if (S_ISREG(i->i_mode)) {
+		fnode->file_size = cpu_to_le32(i->i_size);
+		if (de) de->file_size = cpu_to_le32(i->i_size);
+	} else if (S_ISDIR(i->i_mode)) {
+		fnode->file_size = cpu_to_le32(0);
+		if (de) de->file_size = cpu_to_le32(0);
+	}
+	hpfs_write_inode_ea(i, fnode);
+	if (de) {
+		de->write_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_mtime_sec(i)));
+		de->read_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_atime_sec(i)));
+		de->creation_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_ctime_sec(i)));
+		de->read_only = !(i->i_mode & 0222);
+		de->ea_size = cpu_to_le32(hpfs_inode->i_ea_size);
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+	}
+	if (S_ISDIR(i->i_mode)) {
+		if ((de = map_dirent(i, hpfs_inode->i_dno, "\001\001", 2, NULL, &qbh))) {
+			de->write_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_mtime_sec(i)));
+			de->read_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_atime_sec(i)));
+			de->creation_date = cpu_to_le32(gmt_to_local(i->i_sb, inode_get_ctime_sec(i)));
+			de->read_only = !(i->i_mode & 0222);
+			de->ea_size = cpu_to_le32(/*hpfs_inode->i_ea_size*/0);
+			de->file_size = cpu_to_le32(0);
+			hpfs_mark_4buffers_dirty(&qbh);
+			hpfs_brelse4(&qbh);
+		} else
+			hpfs_error(i->i_sb,
+				"directory %08llx doesn't have '.' entry",
+				i->i_ino);
+	}
+	mark_buffer_dirty(bh);
+	brelse(bh);
+}
+
+int hpfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		 struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error = -EINVAL;
+
+	hpfs_lock(inode->i_sb);
+	if (inode->i_ino == hpfs_sb(inode->i_sb)->sb_root)
+		goto out_unlock;
+	if ((attr->ia_valid & ATTR_UID) &&
+	    from_kuid(&init_user_ns, attr->ia_uid) >= 0x10000)
+		goto out_unlock;
+	if ((attr->ia_valid & ATTR_GID) &&
+	    from_kgid(&init_user_ns, attr->ia_gid) >= 0x10000)
+		goto out_unlock;
+	if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size > inode->i_size)
+		goto out_unlock;
+
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
+	if (error)
+		goto out_unlock;
+
+	if ((attr->ia_valid & ATTR_SIZE) &&
+	    attr->ia_size != i_size_read(inode)) {
+		error = inode_newsize_ok(inode, attr->ia_size);
+		if (error)
+			goto out_unlock;
+
+		truncate_setsize(inode, attr->ia_size);
+		hpfs_truncate(inode);
+	}
+
+	setattr_copy(&nop_mnt_idmap, inode, attr);
+
+	hpfs_write_inode(inode);
+
+ out_unlock:
+	hpfs_unlock(inode->i_sb);
+	return error;
+}
+
+void hpfs_write_if_changed(struct inode *inode)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
+
+	if (hpfs_inode->i_dirty)
+		hpfs_write_inode(inode);
+}
+
+void hpfs_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	if (!inode->i_nlink) {
+		hpfs_lock(inode->i_sb);
+		hpfs_remove_fnode(inode->i_sb, inode->i_ino);
+		hpfs_unlock(inode->i_sb);
+	}
+}