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, 65 insertions, 0 deletions

diff --git a/arch/mips/boot/ecoff.h b/arch/mips/boot/ecoff.h
new file mode 100644
index 000000000..5be79ebfc
--- /dev/null
+++ b/arch/mips/boot/ecoff.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Some ECOFF definitions.
+ */
+
+#include <stdint.h>
+
+typedef struct filehdr {
+	uint16_t	f_magic;	/* magic number */
+	uint16_t	f_nscns;	/* number of sections */
+	int32_t		f_timdat;	/* time & date stamp */
+	int32_t		f_symptr;	/* file pointer to symbolic header */
+	int32_t		f_nsyms;	/* sizeof(symbolic hdr) */
+	uint16_t	f_opthdr;	/* sizeof(optional hdr) */
+	uint16_t	f_flags;	/* flags */
+} FILHDR;
+#define FILHSZ	sizeof(FILHDR)
+
+#define MIPSEBMAGIC	0x160
+#define MIPSELMAGIC	0x162
+
+typedef struct scnhdr {
+	char		s_name[8];	/* section name */
+	int32_t		s_paddr;	/* physical address, aliased s_nlib */
+	int32_t		s_vaddr;	/* virtual address */
+	int32_t		s_size;		/* section size */
+	int32_t		s_scnptr;	/* file ptr to raw data for section */
+	int32_t		s_relptr;	/* file ptr to relocation */
+	int32_t		s_lnnoptr;	/* file ptr to gp histogram */
+	uint16_t	s_nreloc;	/* number of relocation entries */
+	uint16_t	s_nlnno;	/* number of gp histogram entries */
+	int32_t		s_flags;	/* flags */
+} SCNHDR;
+#define SCNHSZ		sizeof(SCNHDR)
+#define SCNROUND	((int32_t)16)
+
+typedef struct aouthdr {
+	int16_t	magic;		/* see above				*/
+	int16_t	vstamp;		/* version stamp			*/
+	int32_t	tsize;		/* text size in bytes, padded to DW bdry*/
+	int32_t	dsize;		/* initialized data "  "		*/
+	int32_t	bsize;		/* uninitialized data "	  "		*/
+	int32_t	entry;		/* entry pt.				*/
+	int32_t	text_start;	/* base of text used for this file	*/
+	int32_t	data_start;	/* base of data used for this file	*/
+	int32_t	bss_start;	/* base of bss used for this file	*/
+	int32_t	gprmask;	/* general purpose register mask	*/
+	int32_t	cprmask[4];	/* co-processor register masks		*/
+	int32_t	gp_value;	/* the gp value used for this object	*/
+} AOUTHDR;
+#define AOUTHSZ sizeof(AOUTHDR)
+
+#define OMAGIC		0407
+#define NMAGIC		0410
+#define ZMAGIC		0413
+#define SMAGIC		0411
+#define LIBMAGIC	0443
+
+#define N_TXTOFF(f, a) \
+ ((a).magic == ZMAGIC || (a).magic == LIBMAGIC ? 0 : \
+  ((a).vstamp < 23 ? \
+   ((FILHSZ + AOUTHSZ + (f).f_nscns * SCNHSZ + 7) & 0xfffffff8) : \
+   ((FILHSZ + AOUTHSZ + (f).f_nscns * SCNHSZ + SCNROUND-1) & ~(SCNROUND-1)) ) )
+#define N_DATOFF(f, a) \
+  N_TXTOFF(f, a) + (a).tsize;