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, 124 insertions, 0 deletions

diff --git a/fs/smb/server/stats.h b/fs/smb/server/stats.h
new file mode 100644
index 000000000..bc864efa0
--- /dev/null
+++ b/fs/smb/server/stats.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *   Copyright (C) 2025, LG Electronics.
+ *   Author(s): Hyunchul Lee <hyc.lee@gmail.com>
+ *   Copyright (C) 2025, Samsung Electronics.
+ *   Author(s): Vedansh Bhardwaj <v.bhardwaj@samsung.com>
+ */
+
+#ifndef __KSMBD_STATS_H__
+#define __KSMBD_STATS_H__
+
+#include "../common/smb2status.h"
+
+#define KSMBD_COUNTER_MAX_REQS	19
+
+enum {
+	KSMBD_COUNTER_SESSIONS = 0,
+	KSMBD_COUNTER_TREE_CONNS,
+	KSMBD_COUNTER_REQUESTS,
+	KSMBD_COUNTER_STATUS_SUCCESS,
+	KSMBD_COUNTER_STATUS_INFORMATIONAL,
+	KSMBD_COUNTER_STATUS_WARNING,
+	KSMBD_COUNTER_STATUS_ERROR,
+	KSMBD_COUNTER_ERROR_ACCESS_DENIED,
+	KSMBD_COUNTER_ERROR_NOT_FOUND,
+	KSMBD_COUNTER_ERROR_INVALID_PARAMETER,
+	KSMBD_COUNTER_ERROR_SHARING_VIOLATION,
+	KSMBD_COUNTER_ERROR_NOT_SUPPORTED,
+	KSMBD_COUNTER_ERROR_OTHER,
+	KSMBD_COUNTER_READ_BYTES,
+	KSMBD_COUNTER_WRITE_BYTES,
+	KSMBD_COUNTER_FIRST_REQ,
+	KSMBD_COUNTER_LAST_REQ = KSMBD_COUNTER_FIRST_REQ +
+				KSMBD_COUNTER_MAX_REQS - 1,
+	KSMBD_COUNTER_MAX,
+};
+
+#ifdef CONFIG_PROC_FS
+extern struct ksmbd_counters ksmbd_counters;
+
+struct ksmbd_counters {
+	struct percpu_counter	counters[KSMBD_COUNTER_MAX];
+};
+
+static inline void ksmbd_counter_inc(int type)
+{
+	percpu_counter_inc(&ksmbd_counters.counters[type]);
+}
+
+static inline void ksmbd_counter_dec(int type)
+{
+	percpu_counter_dec(&ksmbd_counters.counters[type]);
+}
+
+static inline void ksmbd_counter_add(int type, s64 value)
+{
+	percpu_counter_add(&ksmbd_counters.counters[type], value);
+}
+
+static inline void ksmbd_counter_sub(int type, s64 value)
+{
+	percpu_counter_sub(&ksmbd_counters.counters[type], value);
+}
+
+static inline void ksmbd_counter_inc_reqs(unsigned int cmd, __le32 status)
+{
+	unsigned int severity = le32_to_cpu(status) >> 30;
+	int type;
+
+	switch (severity) {
+	case 0:
+		type = KSMBD_COUNTER_STATUS_SUCCESS;
+		break;
+	case 1:
+		type = KSMBD_COUNTER_STATUS_INFORMATIONAL;
+		break;
+	case 2:
+		type = KSMBD_COUNTER_STATUS_WARNING;
+		break;
+	default:
+		type = KSMBD_COUNTER_STATUS_ERROR;
+		break;
+	}
+	percpu_counter_inc(&ksmbd_counters.counters[type]);
+
+	if (severity == 3) {
+		if (status == STATUS_ACCESS_DENIED)
+			type = KSMBD_COUNTER_ERROR_ACCESS_DENIED;
+		else if (status == STATUS_OBJECT_NAME_NOT_FOUND ||
+			 status == STATUS_NO_SUCH_FILE)
+			type = KSMBD_COUNTER_ERROR_NOT_FOUND;
+		else if (status == STATUS_INVALID_PARAMETER)
+			type = KSMBD_COUNTER_ERROR_INVALID_PARAMETER;
+		else if (status == STATUS_SHARING_VIOLATION)
+			type = KSMBD_COUNTER_ERROR_SHARING_VIOLATION;
+		else if (status == STATUS_NOT_SUPPORTED ||
+			 status == STATUS_NOT_IMPLEMENTED)
+			type = KSMBD_COUNTER_ERROR_NOT_SUPPORTED;
+		else
+			type = KSMBD_COUNTER_ERROR_OTHER;
+		percpu_counter_inc(&ksmbd_counters.counters[type]);
+	}
+
+	if (cmd < KSMBD_COUNTER_MAX_REQS) {
+		percpu_counter_inc(&ksmbd_counters.counters[KSMBD_COUNTER_REQUESTS]);
+		percpu_counter_inc(&ksmbd_counters.counters[KSMBD_COUNTER_FIRST_REQ + cmd]);
+	}
+}
+
+static inline s64 ksmbd_counter_sum(int type)
+{
+	return percpu_counter_sum_positive(&ksmbd_counters.counters[type]);
+}
+#else
+
+static inline void ksmbd_counter_inc(int type) {}
+static inline void ksmbd_counter_dec(int type) {}
+static inline void ksmbd_counter_add(int type, s64 value) {}
+static inline void ksmbd_counter_sub(int type, s64 value) {}
+static inline void ksmbd_counter_inc_reqs(unsigned int cmd, __le32 status) {}
+static inline s64 ksmbd_counter_sum(int type) { return 0; }
+#endif
+
+#endif