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, 95 insertions, 0 deletions

diff --git a/fs/coda/coda_linux.h b/fs/coda/coda_linux.h
new file mode 100644
index 000000000..dd6277d87
--- /dev/null
+++ b/fs/coda/coda_linux.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Coda File System, Linux Kernel module
+ * 
+ * Original version, adapted from cfs_mach.c, (C) Carnegie Mellon University
+ * Linux modifications (C) 1996, Peter J. Braam
+ * Rewritten for Linux 2.1 (C) 1997 Carnegie Mellon University
+ *
+ * Carnegie Mellon University encourages users of this software to
+ * contribute improvements to the Coda project.
+ */
+
+#ifndef _LINUX_CODA_FS
+#define _LINUX_CODA_FS
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/wait.h>		
+#include <linux/types.h>
+#include <linux/fs.h>
+#include "coda_fs_i.h"
+
+/* operations */
+extern const struct inode_operations coda_dir_inode_operations;
+extern const struct inode_operations coda_file_inode_operations;
+extern const struct inode_operations coda_ioctl_inode_operations;
+
+extern const struct dentry_operations coda_dentry_operations;
+
+extern const struct address_space_operations coda_file_aops;
+extern const struct address_space_operations coda_symlink_aops;
+
+extern const struct file_operations coda_dir_operations;
+extern const struct file_operations coda_file_operations;
+extern const struct file_operations coda_ioctl_operations;
+
+/* operations shared over more than one file */
+int coda_open(struct inode *i, struct file *f);
+int coda_release(struct inode *i, struct file *f);
+int coda_permission(struct mnt_idmap *idmap, struct inode *inode,
+		    int mask);
+int coda_revalidate_inode(struct inode *);
+int coda_getattr(struct mnt_idmap *, const struct path *, struct kstat *,
+		 u32, unsigned int);
+int coda_setattr(struct mnt_idmap *, struct dentry *, struct iattr *);
+
+/* this file:  helpers */
+char *coda_f2s(struct CodaFid *f);
+int coda_iscontrol(const char *name, size_t length);
+
+umode_t coda_inode_type(struct coda_vattr *attr);
+void coda_vattr_to_iattr(struct inode *, struct coda_vattr *);
+void coda_iattr_to_vattr(struct iattr *, struct coda_vattr *);
+unsigned short coda_flags_to_cflags(unsigned short);
+
+/* inode to cnode access functions */
+
+static inline struct coda_inode_info *ITOC(struct inode *inode)
+{
+	return container_of(inode, struct coda_inode_info, vfs_inode);
+}
+
+static __inline__ struct CodaFid *coda_i2f(struct inode *inode)
+{
+	return &(ITOC(inode)->c_fid);
+}
+
+static __inline__ char *coda_i2s(struct inode *inode)
+{
+	return coda_f2s(&(ITOC(inode)->c_fid));
+}
+
+/* this will not zap the inode away */
+static __inline__ void coda_flag_inode(struct inode *inode, int flag)
+{
+	struct coda_inode_info *cii = ITOC(inode);
+
+	if (!inode)
+		return;
+
+	spin_lock(&cii->c_lock);
+	cii->c_flags |= flag;
+	spin_unlock(&cii->c_lock);
+}		
+
+#endif