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, 57 insertions, 0 deletions

diff --git a/arch/powerpc/boot/redboot.h b/arch/powerpc/boot/redboot.h
new file mode 100644
index 000000000..8f319b1ad
--- /dev/null
+++ b/arch/powerpc/boot/redboot.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PPC_REDBOOT_H
+#define _PPC_REDBOOT_H
+
+//=========================================================================
+// include/asm-ppc/redboot.h
+//   Copyright (c) 2002, 2003 Gary Thomas (<gary@mlbassoc.com>
+//   Copyright (c) 1997 Dan Malek (dmalek@jlc.net)
+
+//
+// Board specific details, as provided by RedBoot
+//
+
+/* A Board Information structure that is given to a program when
+ * RedBoot starts it up.  Note: not all fields make sense for all
+ * architectures and it's up to the platform specific code to fill
+ * in the details.
+ */
+typedef struct bd_info {
+    unsigned int   bi_tag;        /* Should be 0x42444944 "BDID" */
+    unsigned int   bi_size;       /* Size of this structure */
+    unsigned int   bi_revision;   /* revision of this structure */
+    unsigned int   bi_bdate;      /* bootstrap date, i.e. 0x19971106 */
+    unsigned int   bi_memstart;   /* Memory start address */
+    unsigned int   bi_memsize;    /* Memory (end) size in bytes */
+    unsigned int   bi_intfreq;    /* Internal Freq, in Hz */
+    unsigned int   bi_busfreq;    /* Bus Freq, in Hz */
+    unsigned int   bi_cpmfreq;    /* CPM Freq, in Hz */
+    unsigned int   bi_brgfreq;    /* BRG Freq, in Hz */
+    unsigned int   bi_vco;        /* VCO Out from PLL */
+    unsigned int   bi_pci_freq;   /* PCI Freq, in Hz */
+    unsigned int   bi_baudrate;   /* Default console baud rate */
+    unsigned int   bi_immr;       /* IMMR when called from boot rom */
+    unsigned char  bi_enetaddr[6];
+    unsigned int   bi_flashbase;  /* Physical address of FLASH memory */
+    unsigned int   bi_flashsize;  /* Length of FLASH memory */
+    int            bi_flashwidth; /* Width (8,16,32,64) */
+    unsigned char *bi_cmdline;    /* Pointer to command line */
+    unsigned char  bi_esa[3][6];  /* Ethernet station addresses */
+    unsigned int   bi_ramdisk_begin, bi_ramdisk_end;
+    struct {                      /* Information about [main] video screen */
+        short x_res;              /*   Horizontal resolution in pixels */
+        short y_res;              /*   Vertical resolution in pixels */
+        short bpp;                /*   Bits/pixel */
+        short mode;               /*   Type of pixels (packed, indexed) */
+        unsigned long fb;         /*   Pointer to frame buffer (pixel) memory */
+    } bi_video;
+    void         (*bi_cputc)(char);   /* Write a character to the RedBoot console */
+    char         (*bi_cgetc)(void);   /* Read a character from the RedBoot console */
+    int          (*bi_ctstc)(void);   /* Test for input on the RedBoot console */
+} bd_t;
+
+#define BI_REV 0x0102    /* Version 1.02 */
+
+#define bi_pci_busfreq bi_pci_freq
+#define bi_immr_base   bi_immr
+#endif