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, 40 insertions, 0 deletions

diff --git a/include/uapi/asm-generic/errno-base.h b/include/uapi/asm-generic/errno-base.h
new file mode 100644
index 000000000..9653140bf
--- /dev/null
+++ b/include/uapi/asm-generic/errno-base.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _ASM_GENERIC_ERRNO_BASE_H
+#define _ASM_GENERIC_ERRNO_BASE_H
+
+#define	EPERM		 1	/* Operation not permitted */
+#define	ENOENT		 2	/* No such file or directory */
+#define	ESRCH		 3	/* No such process */
+#define	EINTR		 4	/* Interrupted system call */
+#define	EIO		 5	/* I/O error */
+#define	ENXIO		 6	/* No such device or address */
+#define	E2BIG		 7	/* Argument list too long */
+#define	ENOEXEC		 8	/* Exec format error */
+#define	EBADF		 9	/* Bad file number */
+#define	ECHILD		10	/* No child processes */
+#define	EAGAIN		11	/* Try again */
+#define	ENOMEM		12	/* Out of memory */
+#define	EACCES		13	/* Permission denied */
+#define	EFAULT		14	/* Bad address */
+#define	ENOTBLK		15	/* Block device required */
+#define	EBUSY		16	/* Device or resource busy */
+#define	EEXIST		17	/* File exists */
+#define	EXDEV		18	/* Cross-device link */
+#define	ENODEV		19	/* No such device */
+#define	ENOTDIR		20	/* Not a directory */
+#define	EISDIR		21	/* Is a directory */
+#define	EINVAL		22	/* Invalid argument */
+#define	ENFILE		23	/* File table overflow */
+#define	EMFILE		24	/* Too many open files */
+#define	ENOTTY		25	/* Not a typewriter */
+#define	ETXTBSY		26	/* Text file busy */
+#define	EFBIG		27	/* File too large */
+#define	ENOSPC		28	/* No space left on device */
+#define	ESPIPE		29	/* Illegal seek */
+#define	EROFS		30	/* Read-only file system */
+#define	EMLINK		31	/* Too many links */
+#define	EPIPE		32	/* Broken pipe */
+#define	EDOM		33	/* Math argument out of domain of func */
+#define	ERANGE		34	/* Math result not representable */
+
+#endif