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, 284 insertions, 0 deletions

diff --git a/drivers/base/regmap/trace.h b/drivers/base/regmap/trace.h
new file mode 100644
index 000000000..bcc5a8b22
--- /dev/null
+++ b/drivers/base/regmap/trace.h
@@ -0,0 +1,284 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM regmap
+
+#if !defined(_TRACE_REGMAP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_REGMAP_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+
+#include "internal.h"
+
+/*
+ * Log register events
+ */
+DECLARE_EVENT_CLASS(regmap_reg,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 unsigned int val),
+
+	TP_ARGS(map, reg, val),
+
+	TP_STRUCT__entry(
+		__string(	name,		regmap_name(map)	)
+		__field(	unsigned int,	reg			)
+		__field(	unsigned int,	val			)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->reg = reg;
+		__entry->val = val;
+	),
+
+	TP_printk("%s reg=%x val=%x", __get_str(name), __entry->reg, __entry->val)
+);
+
+DEFINE_EVENT(regmap_reg, regmap_reg_write,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 unsigned int val),
+
+	TP_ARGS(map, reg, val)
+);
+
+DEFINE_EVENT(regmap_reg, regmap_reg_read,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 unsigned int val),
+
+	TP_ARGS(map, reg, val)
+);
+
+DEFINE_EVENT(regmap_reg, regmap_reg_read_cache,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 unsigned int val),
+
+	TP_ARGS(map, reg, val)
+);
+
+DECLARE_EVENT_CLASS(regmap_bulk,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 const void *val, int val_len),
+
+	TP_ARGS(map, reg, val, val_len),
+
+	TP_STRUCT__entry(
+		__string(name, regmap_name(map))
+		__field(unsigned int, reg)
+		__dynamic_array(char, buf, val_len)
+		__field(int, val_len)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->reg = reg;
+		__entry->val_len = val_len;
+		memcpy(__get_dynamic_array(buf), val, val_len);
+	),
+
+	TP_printk("%s reg=%x val=%s", __get_str(name), __entry->reg,
+		  __print_hex(__get_dynamic_array(buf), __entry->val_len))
+);
+
+DEFINE_EVENT(regmap_bulk, regmap_bulk_write,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 const void *val, int val_len),
+
+	TP_ARGS(map, reg, val, val_len)
+);
+
+DEFINE_EVENT(regmap_bulk, regmap_bulk_read,
+
+	TP_PROTO(struct regmap *map, unsigned int reg,
+		 const void *val, int val_len),
+
+	TP_ARGS(map, reg, val, val_len)
+);
+
+DECLARE_EVENT_CLASS(regmap_block,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count),
+
+	TP_STRUCT__entry(
+		__string(	name,		regmap_name(map)	)
+		__field(	unsigned int,	reg			)
+		__field(	int,		count			)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->reg = reg;
+		__entry->count = count;
+	),
+
+	TP_printk("%s reg=%x count=%d", __get_str(name), __entry->reg, __entry->count)
+);
+
+DEFINE_EVENT(regmap_block, regmap_hw_read_start,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count)
+);
+
+DEFINE_EVENT(regmap_block, regmap_hw_read_done,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count)
+);
+
+DEFINE_EVENT(regmap_block, regmap_hw_write_start,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count)
+);
+
+DEFINE_EVENT(regmap_block, regmap_hw_write_done,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count)
+);
+
+TRACE_EVENT(regcache_sync,
+
+	TP_PROTO(struct regmap *map, const char *type,
+		 const char *status),
+
+	TP_ARGS(map, type, status),
+
+	TP_STRUCT__entry(
+		__string(       name,           regmap_name(map)	)
+		__string(	status,		status			)
+		__string(	type,		type			)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__assign_str(status);
+		__assign_str(type);
+	),
+
+	TP_printk("%s type=%s status=%s", __get_str(name),
+		  __get_str(type), __get_str(status))
+);
+
+DECLARE_EVENT_CLASS(regmap_bool,
+
+	TP_PROTO(struct regmap *map, bool flag),
+
+	TP_ARGS(map, flag),
+
+	TP_STRUCT__entry(
+		__string(	name,		regmap_name(map)	)
+		__field(	int,		flag			)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->flag = flag;
+	),
+
+	TP_printk("%s flag=%d", __get_str(name), __entry->flag)
+);
+
+DEFINE_EVENT(regmap_bool, regmap_cache_only,
+
+	TP_PROTO(struct regmap *map, bool flag),
+
+	TP_ARGS(map, flag)
+);
+
+DEFINE_EVENT(regmap_bool, regmap_cache_bypass,
+
+	TP_PROTO(struct regmap *map, bool flag),
+
+	TP_ARGS(map, flag)
+);
+
+DECLARE_EVENT_CLASS(regmap_async,
+
+	TP_PROTO(struct regmap *map),
+
+	TP_ARGS(map),
+
+	TP_STRUCT__entry(
+		__string(	name,		regmap_name(map)	)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+	),
+
+	TP_printk("%s", __get_str(name))
+);
+
+DEFINE_EVENT(regmap_block, regmap_async_write_start,
+
+	TP_PROTO(struct regmap *map, unsigned int reg, int count),
+
+	TP_ARGS(map, reg, count)
+);
+
+DEFINE_EVENT(regmap_async, regmap_async_io_complete,
+
+	TP_PROTO(struct regmap *map),
+
+	TP_ARGS(map)
+);
+
+DEFINE_EVENT(regmap_async, regmap_async_complete_start,
+
+	TP_PROTO(struct regmap *map),
+
+	TP_ARGS(map)
+);
+
+DEFINE_EVENT(regmap_async, regmap_async_complete_done,
+
+	TP_PROTO(struct regmap *map),
+
+	TP_ARGS(map)
+);
+
+TRACE_EVENT(regcache_drop_region,
+
+	TP_PROTO(struct regmap *map, unsigned int from,
+		 unsigned int to),
+
+	TP_ARGS(map, from, to),
+
+	TP_STRUCT__entry(
+		__string(       name,           regmap_name(map)	)
+		__field(	unsigned int,	from			)
+		__field(	unsigned int,	to			)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->from = from;
+		__entry->to = to;
+	),
+
+	TP_printk("%s %u-%u", __get_str(name), __entry->from, __entry->to)
+);
+
+#endif /* _TRACE_REGMAP_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>