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, 266 insertions, 0 deletions

diff --git a/drivers/ssb/ssb_private.h b/drivers/ssb/ssb_private.h
new file mode 100644
index 000000000..5f31bdfbe
--- /dev/null
+++ b/drivers/ssb/ssb_private.h
@@ -0,0 +1,266 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_SSB_PRIVATE_H_
+#define LINUX_SSB_PRIVATE_H_
+
+#define PFX		"ssb: "
+#define pr_fmt(fmt)	PFX fmt
+
+#include <linux/ssb/ssb.h>
+#include <linux/types.h>
+#include <linux/bcm47xx_wdt.h>
+
+
+/* pci.c */
+#ifdef CONFIG_SSB_PCIHOST
+extern int ssb_pci_switch_core(struct ssb_bus *bus,
+			       struct ssb_device *dev);
+extern int ssb_pci_switch_coreidx(struct ssb_bus *bus,
+				  u8 coreidx);
+extern int ssb_pci_xtal(struct ssb_bus *bus, u32 what,
+			int turn_on);
+extern int ssb_pci_get_invariants(struct ssb_bus *bus,
+				  struct ssb_init_invariants *iv);
+extern void ssb_pci_exit(struct ssb_bus *bus);
+extern int ssb_pci_init(struct ssb_bus *bus);
+extern const struct ssb_bus_ops ssb_pci_ops;
+
+#else /* CONFIG_SSB_PCIHOST */
+
+static inline int ssb_pci_switch_core(struct ssb_bus *bus,
+				      struct ssb_device *dev)
+{
+	return 0;
+}
+static inline int ssb_pci_switch_coreidx(struct ssb_bus *bus,
+					 u8 coreidx)
+{
+	return 0;
+}
+static inline int ssb_pci_xtal(struct ssb_bus *bus, u32 what,
+			       int turn_on)
+{
+	return 0;
+}
+static inline void ssb_pci_exit(struct ssb_bus *bus)
+{
+}
+static inline int ssb_pci_init(struct ssb_bus *bus)
+{
+	return 0;
+}
+#endif /* CONFIG_SSB_PCIHOST */
+
+
+/* pcmcia.c */
+#ifdef CONFIG_SSB_PCMCIAHOST
+extern int ssb_pcmcia_switch_coreidx(struct ssb_bus *bus,
+				     u8 coreidx);
+extern int ssb_pcmcia_switch_segment(struct ssb_bus *bus,
+				     u8 seg);
+extern int ssb_pcmcia_get_invariants(struct ssb_bus *bus,
+				     struct ssb_init_invariants *iv);
+extern int ssb_pcmcia_hardware_setup(struct ssb_bus *bus);
+extern void ssb_pcmcia_exit(struct ssb_bus *bus);
+extern int ssb_pcmcia_init(struct ssb_bus *bus);
+extern int ssb_host_pcmcia_init(void);
+extern void ssb_host_pcmcia_exit(void);
+extern const struct ssb_bus_ops ssb_pcmcia_ops;
+#else /* CONFIG_SSB_PCMCIAHOST */
+static inline int ssb_pcmcia_switch_coreidx(struct ssb_bus *bus,
+					    u8 coreidx)
+{
+	return 0;
+}
+static inline int ssb_pcmcia_switch_segment(struct ssb_bus *bus,
+					    u8 seg)
+{
+	return 0;
+}
+static inline int ssb_pcmcia_hardware_setup(struct ssb_bus *bus)
+{
+	return 0;
+}
+static inline void ssb_pcmcia_exit(struct ssb_bus *bus)
+{
+}
+static inline int ssb_pcmcia_init(struct ssb_bus *bus)
+{
+	return 0;
+}
+static inline int ssb_host_pcmcia_init(void)
+{
+	return 0;
+}
+static inline void ssb_host_pcmcia_exit(void)
+{
+}
+#endif /* CONFIG_SSB_PCMCIAHOST */
+
+/* sdio.c */
+#ifdef CONFIG_SSB_SDIOHOST
+extern int ssb_sdio_get_invariants(struct ssb_bus *bus,
+				     struct ssb_init_invariants *iv);
+
+extern u32 ssb_sdio_scan_read32(struct ssb_bus *bus, u16 offset);
+extern int ssb_sdio_scan_switch_coreidx(struct ssb_bus *bus, u8 coreidx);
+extern void ssb_sdio_exit(struct ssb_bus *bus);
+extern int ssb_sdio_init(struct ssb_bus *bus);
+
+extern const struct ssb_bus_ops ssb_sdio_ops;
+#else /* CONFIG_SSB_SDIOHOST */
+static inline u32 ssb_sdio_scan_read32(struct ssb_bus *bus, u16 offset)
+{
+	return 0;
+}
+static inline int ssb_sdio_scan_switch_coreidx(struct ssb_bus *bus, u8 coreidx)
+{
+	return 0;
+}
+static inline void ssb_sdio_exit(struct ssb_bus *bus)
+{
+}
+static inline int ssb_sdio_init(struct ssb_bus *bus)
+{
+	return 0;
+}
+#endif /* CONFIG_SSB_SDIOHOST */
+
+/**************************************************
+ * host_soc.c
+ **************************************************/
+
+#ifdef CONFIG_SSB_HOST_SOC
+extern const struct ssb_bus_ops ssb_host_soc_ops;
+
+extern int ssb_host_soc_get_invariants(struct ssb_bus *bus,
+				       struct ssb_init_invariants *iv);
+#endif
+
+/* scan.c */
+extern const char *ssb_core_name(u16 coreid);
+extern int ssb_bus_scan(struct ssb_bus *bus,
+			unsigned long baseaddr);
+extern void ssb_iounmap(struct ssb_bus *ssb);
+
+
+/* sprom.c */
+extern
+ssize_t ssb_attr_sprom_show(struct ssb_bus *bus, char *buf,
+			    int (*sprom_read)(struct ssb_bus *bus, u16 *sprom));
+extern
+ssize_t ssb_attr_sprom_store(struct ssb_bus *bus,
+			     const char *buf, size_t count,
+			     int (*sprom_check_crc)(const u16 *sprom, size_t size),
+			     int (*sprom_write)(struct ssb_bus *bus, const u16 *sprom));
+extern int ssb_fill_sprom_with_fallback(struct ssb_bus *bus,
+					struct ssb_sprom *out);
+
+
+/* core.c */
+extern u32 ssb_calc_clock_rate(u32 plltype, u32 n, u32 m);
+extern struct ssb_bus *ssb_pci_dev_to_bus(struct pci_dev *pdev);
+int ssb_for_each_bus_call(unsigned long data,
+			  int (*func)(struct ssb_bus *bus, unsigned long data));
+extern struct ssb_bus *ssb_pcmcia_dev_to_bus(struct pcmcia_device *pdev);
+
+struct ssb_freeze_context {
+	/* Pointer to the bus */
+	struct ssb_bus *bus;
+	/* Boolean list to indicate whether a device is frozen on this bus. */
+	bool device_frozen[SSB_MAX_NR_CORES];
+};
+extern int ssb_devices_freeze(struct ssb_bus *bus, struct ssb_freeze_context *ctx);
+extern int ssb_devices_thaw(struct ssb_freeze_context *ctx);
+
+
+
+/* b43_pci_bridge.c */
+#ifdef CONFIG_SSB_B43_PCI_BRIDGE
+extern int __init b43_pci_ssb_bridge_init(void);
+extern void __exit b43_pci_ssb_bridge_exit(void);
+#else /* CONFIG_SSB_B43_PCI_BRIDGE */
+static inline int b43_pci_ssb_bridge_init(void)
+{
+	return 0;
+}
+static inline void b43_pci_ssb_bridge_exit(void)
+{
+}
+#endif /* CONFIG_SSB_B43_PCI_BRIDGE */
+
+/* driver_chipcommon_pmu.c */
+extern u32 ssb_pmu_get_cpu_clock(struct ssb_chipcommon *cc);
+extern u32 ssb_pmu_get_controlclock(struct ssb_chipcommon *cc);
+extern u32 ssb_pmu_get_alp_clock(struct ssb_chipcommon *cc);
+
+extern u32 ssb_chipco_watchdog_timer_set_wdt(struct bcm47xx_wdt *wdt,
+					     u32 ticks);
+extern u32 ssb_chipco_watchdog_timer_set_ms(struct bcm47xx_wdt *wdt, u32 ms);
+
+/* driver_chipcommon_sflash.c */
+#ifdef CONFIG_SSB_SFLASH
+int ssb_sflash_init(struct ssb_chipcommon *cc);
+#else
+static inline int ssb_sflash_init(struct ssb_chipcommon *cc)
+{
+	pr_err("Serial flash not supported\n");
+	return 0;
+}
+#endif /* CONFIG_SSB_SFLASH */
+
+#ifdef CONFIG_SSB_DRIVER_MIPS
+extern struct platform_device ssb_pflash_dev;
+#endif
+
+#ifdef CONFIG_SSB_SFLASH
+extern struct platform_device ssb_sflash_dev;
+#endif
+
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+extern u32 ssb_extif_watchdog_timer_set_wdt(struct bcm47xx_wdt *wdt, u32 ticks);
+extern u32 ssb_extif_watchdog_timer_set_ms(struct bcm47xx_wdt *wdt, u32 ms);
+#else
+static inline u32 ssb_extif_watchdog_timer_set_wdt(struct bcm47xx_wdt *wdt,
+						   u32 ticks)
+{
+	return 0;
+}
+static inline u32 ssb_extif_watchdog_timer_set_ms(struct bcm47xx_wdt *wdt,
+						  u32 ms)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_SSB_EMBEDDED
+extern int ssb_watchdog_register(struct ssb_bus *bus);
+#else /* CONFIG_SSB_EMBEDDED */
+static inline int ssb_watchdog_register(struct ssb_bus *bus)
+{
+	return 0;
+}
+#endif /* CONFIG_SSB_EMBEDDED */
+
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+extern void ssb_extif_init(struct ssb_extif *extif);
+#else
+static inline void ssb_extif_init(struct ssb_extif *extif)
+{
+}
+#endif
+
+#ifdef CONFIG_SSB_DRIVER_GPIO
+extern int ssb_gpio_init(struct ssb_bus *bus);
+extern int ssb_gpio_unregister(struct ssb_bus *bus);
+#else /* CONFIG_SSB_DRIVER_GPIO */
+static inline int ssb_gpio_init(struct ssb_bus *bus)
+{
+	return -ENOTSUPP;
+}
+static inline int ssb_gpio_unregister(struct ssb_bus *bus)
+{
+	return 0;
+}
+#endif /* CONFIG_SSB_DRIVER_GPIO */
+
+#endif /* LINUX_SSB_PRIVATE_H_ */