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, 265 insertions, 0 deletions

diff --git a/arch/mips/sni/setup.c b/arch/mips/sni/setup.c
new file mode 100644
index 000000000..fc7da1228
--- /dev/null
+++ b/arch/mips/sni/setup.c
@@ -0,0 +1,265 @@
+/*
+ * Setup pointers to hardware-dependent routines.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1996, 97, 98, 2000, 03, 04, 06 Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2006,2007 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
+ */
+#include <linux/eisa.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/console.h>
+#include <linux/screen_info.h>
+#include <linux/string.h>
+
+#ifdef CONFIG_FW_ARC
+#include <asm/fw/arc/types.h>
+#include <asm/sgialib.h>
+#endif
+
+#ifdef CONFIG_FW_SNIPROM
+#include <asm/mipsprom.h>
+#endif
+
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/io.h>
+#include <asm/reboot.h>
+#include <asm/sni.h>
+
+unsigned int sni_brd_type;
+EXPORT_SYMBOL(sni_brd_type);
+
+extern void sni_machine_restart(char *command);
+extern void sni_machine_power_off(void);
+
+static void __init sni_display_setup(void)
+{
+#if defined(CONFIG_VGA_CONSOLE) && defined(CONFIG_FW_ARC)
+	static struct screen_info si;
+	DISPLAY_STATUS *di;
+
+	di = ArcGetDisplayStatus(1);
+
+	if (di) {
+		si.orig_x		= di->CursorXPosition;
+		si.orig_y		= di->CursorYPosition;
+		si.orig_video_cols	= di->CursorMaxXPosition;
+		si.orig_video_lines	= di->CursorMaxYPosition;
+		si.orig_video_isVGA	= VIDEO_TYPE_VGAC;
+		si.orig_video_points	= 16;
+
+		vgacon_register_screen(&si);
+	}
+#endif
+}
+
+static void __init sni_console_setup(void)
+{
+#ifndef CONFIG_FW_ARC
+	char *ctype;
+	char *cdev;
+	char *baud;
+	int port;
+	static char options[8] __initdata;
+
+	cdev = prom_getenv("console_dev");
+	if (strncmp(cdev, "tty", 3) == 0) {
+		ctype = prom_getenv("console");
+		switch (*ctype) {
+		default:
+		case 'l':
+			port = 0;
+			baud = prom_getenv("lbaud");
+			break;
+		case 'r':
+			port = 1;
+			baud = prom_getenv("rbaud");
+			break;
+		}
+		if (baud)
+			strscpy(options, baud);
+		if (strncmp(cdev, "tty552", 6) == 0)
+			add_preferred_console("ttyS", port,
+					      baud ? options : NULL);
+		else
+			add_preferred_console("ttySC", port,
+					      baud ? options : NULL);
+	}
+#endif
+}
+
+#ifdef DEBUG
+static void __init sni_idprom_dump(void)
+{
+	int	i;
+
+	pr_debug("SNI IDProm dump:\n");
+	for (i = 0; i < 256; i++) {
+		if (i%16 == 0)
+			pr_debug("%04x ", i);
+
+		printk("%02x ", *(unsigned char *) (SNI_IDPROM_BASE + i));
+
+		if (i % 16 == 15)
+			printk("\n");
+	}
+}
+#endif
+
+void __init plat_mem_setup(void)
+{
+	int cputype;
+
+	set_io_port_base(SNI_PORT_BASE);
+//	ioport_resource.end = sni_io_resource.end;
+
+	/*
+	 * Setup (E)ISA I/O memory access stuff
+	 */
+#ifdef CONFIG_EISA
+	EISA_bus = 1;
+#endif
+
+	sni_brd_type = *(unsigned char *)SNI_IDPROM_BRDTYPE;
+	cputype = *(unsigned char *)SNI_IDPROM_CPUTYPE;
+	switch (sni_brd_type) {
+	case SNI_BRD_TOWER_OASIC:
+		switch (cputype) {
+		case SNI_CPU_M8030:
+			system_type = "RM400-330";
+			break;
+		case SNI_CPU_M8031:
+			system_type = "RM400-430";
+			break;
+		case SNI_CPU_M8037:
+			system_type = "RM400-530";
+			break;
+		case SNI_CPU_M8034:
+			system_type = "RM400-730";
+			break;
+		default:
+			system_type = "RM400-xxx";
+			break;
+		}
+		break;
+	case SNI_BRD_MINITOWER:
+		switch (cputype) {
+		case SNI_CPU_M8021:
+		case SNI_CPU_M8043:
+			system_type = "RM400-120";
+			break;
+		case SNI_CPU_M8040:
+			system_type = "RM400-220";
+			break;
+		case SNI_CPU_M8053:
+			system_type = "RM400-225";
+			break;
+		case SNI_CPU_M8050:
+			system_type = "RM400-420";
+			break;
+		default:
+			system_type = "RM400-xxx";
+			break;
+		}
+		break;
+	case SNI_BRD_PCI_TOWER:
+		system_type = "RM400-Cxx";
+		break;
+	case SNI_BRD_RM200:
+		system_type = "RM200-xxx";
+		break;
+	case SNI_BRD_PCI_MTOWER:
+		system_type = "RM300-Cxx";
+		break;
+	case SNI_BRD_PCI_DESKTOP:
+		switch (read_c0_prid() & PRID_IMP_MASK) {
+		case PRID_IMP_R4600:
+		case PRID_IMP_R4700:
+			system_type = "RM200-C20";
+			break;
+		case PRID_IMP_R5000:
+			system_type = "RM200-C40";
+			break;
+		default:
+			system_type = "RM200-Cxx";
+			break;
+		}
+		break;
+	case SNI_BRD_PCI_TOWER_CPLUS:
+		system_type = "RM400-Exx";
+		break;
+	case SNI_BRD_PCI_MTOWER_CPLUS:
+		system_type = "RM300-Exx";
+		break;
+	}
+	pr_debug("Found SNI brdtype %02x name %s\n", sni_brd_type, system_type);
+
+#ifdef DEBUG
+	sni_idprom_dump();
+#endif
+
+	switch (sni_brd_type) {
+	case SNI_BRD_10:
+	case SNI_BRD_10NEW:
+	case SNI_BRD_TOWER_OASIC:
+	case SNI_BRD_MINITOWER:
+		sni_a20r_init();
+		break;
+
+	case SNI_BRD_PCI_TOWER:
+	case SNI_BRD_PCI_TOWER_CPLUS:
+		sni_pcit_init();
+		break;
+
+	case SNI_BRD_RM200:
+		sni_rm200_init();
+		break;
+
+	case SNI_BRD_PCI_MTOWER:
+	case SNI_BRD_PCI_DESKTOP:
+	case SNI_BRD_PCI_MTOWER_CPLUS:
+		sni_pcimt_init();
+		break;
+	}
+
+	_machine_restart = sni_machine_restart;
+	pm_power_off = sni_machine_power_off;
+
+	sni_display_setup();
+	sni_console_setup();
+}
+
+#ifdef CONFIG_PCI
+
+#include <linux/pci.h>
+#include <video/vga.h>
+#include <video/cirrus.h>
+
+static void quirk_cirrus_ram_size(struct pci_dev *dev)
+{
+	u16 cmd;
+
+	/*
+	 * firmware doesn't set the ram size correct, so we
+	 * need to do it here, otherwise we get screen corruption
+	 * on older Cirrus chips
+	 */
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	if ((cmd & (PCI_COMMAND_IO|PCI_COMMAND_MEMORY))
+		== (PCI_COMMAND_IO|PCI_COMMAND_MEMORY)) {
+		vga_wseq(NULL, CL_SEQR6, 0x12); /* unlock all extension registers */
+		vga_wseq(NULL, CL_SEQRF, 0x18);
+	}
+}
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CIRRUS, PCI_DEVICE_ID_CIRRUS_5434_8,
+			quirk_cirrus_ram_size);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CIRRUS, PCI_DEVICE_ID_CIRRUS_5436,
+			quirk_cirrus_ram_size);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CIRRUS, PCI_DEVICE_ID_CIRRUS_5446,
+			quirk_cirrus_ram_size);
+#endif