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, 158 insertions, 0 deletions

diff --git a/fs/jfs/file.c b/fs/jfs/file.c
new file mode 100644
index 000000000..246568cb9
--- /dev/null
+++ b/fs/jfs/file.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) International Business Machines Corp., 2000-2002
+ *   Portions Copyright (C) Christoph Hellwig, 2001-2002
+ */
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/filelock.h>
+#include <linux/posix_acl.h>
+#include <linux/quotaops.h>
+#include "jfs_incore.h"
+#include "jfs_inode.h"
+#include "jfs_dmap.h"
+#include "jfs_txnmgr.h"
+#include "jfs_xattr.h"
+#include "jfs_acl.h"
+#include "jfs_debug.h"
+
+int jfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = file->f_mapping->host;
+	int rc = 0;
+
+	rc = file_write_and_wait_range(file, start, end);
+	if (rc)
+		return rc;
+
+	inode_lock(inode);
+	if (!(inode_state_read_once(inode) & I_DIRTY_ALL) ||
+	    (datasync && !(inode_state_read_once(inode) & I_DIRTY_DATASYNC))) {
+		/* Make sure committed changes hit the disk */
+		jfs_flush_journal(JFS_SBI(inode->i_sb)->log, 1);
+		inode_unlock(inode);
+		return rc;
+	}
+
+	rc |= jfs_commit_inode(inode, 1);
+	inode_unlock(inode);
+
+	return rc ? -EIO : 0;
+}
+
+static int jfs_open(struct inode *inode, struct file *file)
+{
+	int rc;
+
+	if (S_ISREG(inode->i_mode) && inode->i_size < 0)
+		return -EIO;
+
+	if ((rc = dquot_file_open(inode, file)))
+		return rc;
+
+	/*
+	 * We attempt to allow only one "active" file open per aggregate
+	 * group.  Otherwise, appending to files in parallel can cause
+	 * fragmentation within the files.
+	 *
+	 * If the file is empty, it was probably just created and going
+	 * to be written to.  If it has a size, we'll hold off until the
+	 * file is actually grown.
+	 */
+	if (S_ISREG(inode->i_mode) && file->f_mode & FMODE_WRITE &&
+	    (inode->i_size == 0)) {
+		struct jfs_inode_info *ji = JFS_IP(inode);
+		spin_lock_irq(&ji->ag_lock);
+		if (ji->active_ag == -1) {
+			struct jfs_sb_info *jfs_sb = JFS_SBI(inode->i_sb);
+			ji->active_ag = BLKTOAG(addressPXD(&ji->ixpxd), jfs_sb);
+			atomic_inc(&jfs_sb->bmap->db_active[ji->active_ag]);
+		}
+		spin_unlock_irq(&ji->ag_lock);
+	}
+
+	return 0;
+}
+static int jfs_release(struct inode *inode, struct file *file)
+{
+	struct jfs_inode_info *ji = JFS_IP(inode);
+
+	spin_lock_irq(&ji->ag_lock);
+	if (ji->active_ag != -1) {
+		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
+		atomic_dec(&bmap->db_active[ji->active_ag]);
+		ji->active_ag = -1;
+	}
+	spin_unlock_irq(&ji->ag_lock);
+
+	return 0;
+}
+
+int jfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	int rc;
+
+	rc = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
+	if (rc)
+		return rc;
+
+	if (is_quota_modification(&nop_mnt_idmap, inode, iattr)) {
+		rc = dquot_initialize(inode);
+		if (rc)
+			return rc;
+	}
+	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
+	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
+		rc = dquot_transfer(&nop_mnt_idmap, inode, iattr);
+		if (rc)
+			return rc;
+	}
+
+	if ((iattr->ia_valid & ATTR_SIZE) &&
+	    iattr->ia_size != i_size_read(inode)) {
+		inode_dio_wait(inode);
+
+		rc = inode_newsize_ok(inode, iattr->ia_size);
+		if (rc)
+			return rc;
+
+		truncate_setsize(inode, iattr->ia_size);
+		jfs_truncate(inode);
+	}
+
+	setattr_copy(&nop_mnt_idmap, inode, iattr);
+	mark_inode_dirty(inode);
+
+	if (iattr->ia_valid & ATTR_MODE)
+		rc = posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
+	return rc;
+}
+
+const struct inode_operations jfs_file_inode_operations = {
+	.listxattr	= jfs_listxattr,
+	.setattr	= jfs_setattr,
+	.fileattr_get	= jfs_fileattr_get,
+	.fileattr_set	= jfs_fileattr_set,
+#ifdef CONFIG_JFS_POSIX_ACL
+	.get_inode_acl	= jfs_get_acl,
+	.set_acl	= jfs_set_acl,
+#endif
+};
+
+const struct file_operations jfs_file_operations = {
+	.open		= jfs_open,
+	.llseek		= generic_file_llseek,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= generic_file_write_iter,
+	.mmap_prepare	= generic_file_mmap_prepare,
+	.splice_read	= filemap_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.fsync		= jfs_fsync,
+	.release	= jfs_release,
+	.unlocked_ioctl = jfs_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.setlease	= generic_setlease,
+};