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, 189 insertions, 0 deletions

diff --git a/drivers/block/rnbd/rnbd-srv-trace.h b/drivers/block/rnbd/rnbd-srv-trace.h
new file mode 100644
index 000000000..18ae2ed55
--- /dev/null
+++ b/drivers/block/rnbd/rnbd-srv-trace.h
@@ -0,0 +1,189 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2022 1&1 IONOS SE. All rights reserved.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rnbd_srv
+
+#if !defined(_TRACE_RNBD_SRV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RNBD_SRV_H
+
+#include <linux/tracepoint.h>
+
+struct rnbd_srv_session;
+struct rtrs_srv_op;
+
+DECLARE_EVENT_CLASS(rnbd_srv_link_class,
+	TP_PROTO(struct rnbd_srv_session *srv),
+
+	TP_ARGS(srv),
+
+	TP_STRUCT__entry(
+		__field(int, qdepth)
+		__string(sessname, srv->sessname)
+	),
+
+	TP_fast_assign(
+		__entry->qdepth = srv->queue_depth;
+		__assign_str(sessname);
+	),
+
+	TP_printk("sessname: %s qdepth: %d",
+		   __get_str(sessname),
+		   __entry->qdepth
+	)
+);
+
+#define DEFINE_LINK_EVENT(name) \
+DEFINE_EVENT(rnbd_srv_link_class, name, \
+	TP_PROTO(struct rnbd_srv_session *srv), \
+	TP_ARGS(srv))
+
+DEFINE_LINK_EVENT(create_sess);
+DEFINE_LINK_EVENT(destroy_sess);
+
+TRACE_EVENT(process_rdma,
+	TP_PROTO(struct rnbd_srv_session *srv,
+		 const struct rnbd_msg_io *msg,
+		 struct rtrs_srv_op *id,
+		 u32 datalen,
+		 size_t usrlen),
+
+	TP_ARGS(srv, msg, id, datalen, usrlen),
+
+	TP_STRUCT__entry(
+		__string(sessname, srv->sessname)
+		__field(u8, dir)
+		__field(u8, ver)
+		__field(u32, device_id)
+		__field(u64, sector)
+		__field(u32, flags)
+		__field(u32, bi_size)
+		__field(u16, ioprio)
+		__field(u32, datalen)
+		__field(size_t, usrlen)
+	),
+
+	TP_fast_assign(
+		__assign_str(sessname);
+		__entry->dir = id->dir;
+		__entry->ver = srv->ver;
+		__entry->device_id = le32_to_cpu(msg->device_id);
+		__entry->sector = le64_to_cpu(msg->sector);
+		__entry->bi_size = le32_to_cpu(msg->bi_size);
+		__entry->flags = le32_to_cpu(msg->rw);
+		__entry->ioprio = le16_to_cpu(msg->prio);
+		__entry->datalen = datalen;
+		__entry->usrlen = usrlen;
+	),
+
+	TP_printk("I/O req: sess: %s, type: %s, ver: %d, devid: %u, sector: %llu, bsize: %u, flags: %u, ioprio: %d, datalen: %u, usrlen: %zu",
+		   __get_str(sessname),
+		   __print_symbolic(__entry->dir,
+			 { READ,  "READ" },
+			 { WRITE, "WRITE" }),
+		   __entry->ver,
+		   __entry->device_id,
+		   __entry->sector,
+		   __entry->bi_size,
+		   __entry->flags,
+		   __entry->ioprio,
+		   __entry->datalen,
+		   __entry->usrlen
+	)
+);
+
+TRACE_EVENT(process_msg_sess_info,
+	TP_PROTO(struct rnbd_srv_session *srv,
+		 const struct rnbd_msg_sess_info *msg),
+
+	TP_ARGS(srv, msg),
+
+	TP_STRUCT__entry(
+		__field(u8, proto_ver)
+		__field(u8, clt_ver)
+		__field(u8, srv_ver)
+		__string(sessname, srv->sessname)
+	),
+
+	TP_fast_assign(
+		__entry->proto_ver = srv->ver;
+		__entry->clt_ver = msg->ver;
+		__entry->srv_ver = RNBD_PROTO_VER_MAJOR;
+		__assign_str(sessname);
+	),
+
+	TP_printk("Session %s using proto-ver %d (clt-ver: %d, srv-ver: %d)",
+		   __get_str(sessname),
+		   __entry->proto_ver,
+		   __entry->clt_ver,
+		   __entry->srv_ver
+	)
+);
+
+TRACE_DEFINE_ENUM(RNBD_ACCESS_RO);
+TRACE_DEFINE_ENUM(RNBD_ACCESS_RW);
+TRACE_DEFINE_ENUM(RNBD_ACCESS_MIGRATION);
+
+#define show_rnbd_access_mode(x) \
+	__print_symbolic(x, \
+		{ RNBD_ACCESS_RO,		"RO" }, \
+		{ RNBD_ACCESS_RW,		"RW" }, \
+		{ RNBD_ACCESS_MIGRATION,	"MIGRATION" })
+
+TRACE_EVENT(process_msg_open,
+	TP_PROTO(struct rnbd_srv_session *srv,
+		 const struct rnbd_msg_open *msg),
+
+	TP_ARGS(srv, msg),
+
+	TP_STRUCT__entry(
+		__field(u8, access_mode)
+		__string(sessname, srv->sessname)
+		__string(dev_name, msg->dev_name)
+	),
+
+	TP_fast_assign(
+		__entry->access_mode = msg->access_mode;
+		__assign_str(sessname);
+		__assign_str(dev_name);
+	),
+
+	TP_printk("Open message received: session='%s' path='%s' access_mode=%s",
+		   __get_str(sessname),
+		   __get_str(dev_name),
+		   show_rnbd_access_mode(__entry->access_mode)
+	)
+);
+
+TRACE_EVENT(process_msg_close,
+	TP_PROTO(struct rnbd_srv_session *srv,
+		 const struct rnbd_msg_close *msg),
+
+	TP_ARGS(srv, msg),
+
+	TP_STRUCT__entry(
+		__field(u32, device_id)
+		__string(sessname, srv->sessname)
+	),
+
+	TP_fast_assign(
+		__entry->device_id = le32_to_cpu(msg->device_id);
+		__assign_str(sessname);
+	),
+
+	TP_printk("Close message received: session='%s' device id='%d'",
+		   __get_str(sessname),
+		   __entry->device_id
+	)
+);
+
+#endif /* _TRACE_RNBD_SRV_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE rnbd-srv-trace
+#include <trace/define_trace.h>
+