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, 177 insertions, 0 deletions

diff --git a/drivers/cpufreq/amd-pstate-trace.h b/drivers/cpufreq/amd-pstate-trace.h
new file mode 100644
index 000000000..91fa073b2
--- /dev/null
+++ b/drivers/cpufreq/amd-pstate-trace.h
@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * amd-pstate-trace.h - AMD Processor P-state Frequency Driver Tracer
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ * Author: Huang Rui <ray.huang@amd.com>
+ */
+
+#if !defined(_AMD_PSTATE_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _AMD_PSTATE_TRACE_H
+
+#include <linux/cpufreq.h>
+#include <linux/tracepoint.h>
+#include <linux/trace_events.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM amd_cpu
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE amd-pstate-trace
+
+#define TPS(x)  tracepoint_string(x)
+
+TRACE_EVENT(amd_pstate_perf,
+
+	TP_PROTO(u8 min_perf,
+		 u8 target_perf,
+		 u8 capacity,
+		 u64 freq,
+		 u64 mperf,
+		 u64 aperf,
+		 u64 tsc,
+		 unsigned int cpu_id,
+		 bool fast_switch
+		 ),
+
+	TP_ARGS(min_perf,
+		target_perf,
+		capacity,
+		freq,
+		mperf,
+		aperf,
+		tsc,
+		cpu_id,
+		fast_switch
+		),
+
+	TP_STRUCT__entry(
+		__field(u8, min_perf)
+		__field(u8, target_perf)
+		__field(u8, capacity)
+		__field(unsigned long long, freq)
+		__field(unsigned long long, mperf)
+		__field(unsigned long long, aperf)
+		__field(unsigned long long, tsc)
+		__field(unsigned int, cpu_id)
+		__field(bool, fast_switch)
+		),
+
+	TP_fast_assign(
+		__entry->min_perf = min_perf;
+		__entry->target_perf = target_perf;
+		__entry->capacity = capacity;
+		__entry->freq = freq;
+		__entry->mperf = mperf;
+		__entry->aperf = aperf;
+		__entry->tsc = tsc;
+		__entry->cpu_id = cpu_id;
+		__entry->fast_switch = fast_switch;
+		),
+
+	TP_printk("amd_min_perf=%hhu amd_des_perf=%hhu amd_max_perf=%hhu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u fast_switch=%s",
+		  (u8)__entry->min_perf,
+		  (u8)__entry->target_perf,
+		  (u8)__entry->capacity,
+		  (unsigned long long)__entry->freq,
+		  (unsigned long long)__entry->mperf,
+		  (unsigned long long)__entry->aperf,
+		  (unsigned long long)__entry->tsc,
+		  (unsigned int)__entry->cpu_id,
+		  (__entry->fast_switch) ? "true" : "false"
+		 )
+);
+
+TRACE_EVENT(amd_pstate_epp_perf,
+
+	TP_PROTO(unsigned int cpu_id,
+		 u8 highest_perf,
+		 u8 epp,
+		 u8 min_perf,
+		 u8 max_perf,
+		 bool boost,
+		 bool changed
+		 ),
+
+	TP_ARGS(cpu_id,
+		highest_perf,
+		epp,
+		min_perf,
+		max_perf,
+		boost,
+		changed),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu_id)
+		__field(u8, highest_perf)
+		__field(u8, epp)
+		__field(u8, min_perf)
+		__field(u8, max_perf)
+		__field(bool, boost)
+		__field(bool, changed)
+		),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->highest_perf = highest_perf;
+		__entry->epp = epp;
+		__entry->min_perf = min_perf;
+		__entry->max_perf = max_perf;
+		__entry->boost = boost;
+		__entry->changed = changed;
+		),
+
+	TP_printk("cpu%u: [%hhu<->%hhu]/%hhu, epp=%hhu, boost=%u, changed=%u",
+		  (unsigned int)__entry->cpu_id,
+		  (u8)__entry->min_perf,
+		  (u8)__entry->max_perf,
+		  (u8)__entry->highest_perf,
+		  (u8)__entry->epp,
+		  (bool)__entry->boost,
+		  (bool)__entry->changed
+		 )
+);
+
+TRACE_EVENT(amd_pstate_cppc_req2,
+
+	TP_PROTO(unsigned int cpu_id,
+		 u8 floor_perf,
+		 bool changed,
+		 int err_code
+		 ),
+
+	TP_ARGS(cpu_id,
+		floor_perf,
+		changed,
+		err_code),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu_id)
+		__field(u8, floor_perf)
+		__field(bool, changed)
+		__field(int, err_code)
+		),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->floor_perf = floor_perf;
+		__entry->changed = changed;
+		__entry->err_code = err_code;
+		),
+
+	TP_printk("cpu%u: floor_perf=%u, changed=%u (error = %d)",
+		  __entry->cpu_id,
+		  __entry->floor_perf,
+		  __entry->changed,
+		  __entry->err_code
+		 )
+);
+
+#endif /* _AMD_PSTATE_TRACE_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#include <trace/define_trace.h>