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, 95 insertions, 0 deletions

diff --git a/drivers/scsi/aacraid/rkt.c b/drivers/scsi/aacraid/rkt.c
new file mode 100644
index 000000000..8ebc67e54
--- /dev/null
+++ b/drivers/scsi/aacraid/rkt.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Adaptec AAC series RAID controller driver
+ *	(c) Copyright 2001 Red Hat Inc.
+ *
+ * based on the old aacraid driver that is..
+ * Adaptec aacraid device driver for Linux.
+ *
+ * Copyright (c) 2000-2010 Adaptec, Inc.
+ *               2010-2015 PMC-Sierra, Inc. (aacraid@pmc-sierra.com)
+ *		 2016-2017 Microsemi Corp. (aacraid@microsemi.com)
+ *
+ * Module Name:
+ *  rkt.c
+ *
+ * Abstract: Hardware miniport for Drawbridge specific hardware functions.
+ */
+
+#include <linux/blkdev.h>
+
+#include <scsi/scsi_host.h>
+
+#include "aacraid.h"
+
+#define AAC_NUM_IO_FIB_RKT      (246 - AAC_NUM_MGT_FIB)
+
+/**
+ *	aac_rkt_select_comm	-	Select communications method
+ *	@dev: Adapter
+ *	@comm: communications method
+ */
+
+static int aac_rkt_select_comm(struct aac_dev *dev, int comm)
+{
+	int retval;
+	retval = aac_rx_select_comm(dev, comm);
+	if (comm == AAC_COMM_MESSAGE) {
+		/*
+		 * FIB Setup has already been done, but we can minimize the
+		 * damage by at least ensuring the OS never issues more
+		 * commands than we can handle. The Rocket adapters currently
+		 * can only handle 246 commands and 8 AIFs at the same time,
+		 * and in fact do notify us accordingly if we negotiate the
+		 * FIB size. The problem that causes us to add this check is
+		 * to ensure that we do not overdo it with the adapter when a
+		 * hard coded FIB override is being utilized. This special
+		 * case warrants this half baked, but convenient, check here.
+		 */
+		if (dev->scsi_host_ptr->can_queue > AAC_NUM_IO_FIB_RKT) {
+			dev->init->r7.max_io_commands =
+				cpu_to_le32(AAC_NUM_IO_FIB_RKT + AAC_NUM_MGT_FIB);
+			dev->scsi_host_ptr->can_queue = AAC_NUM_IO_FIB_RKT;
+		}
+	}
+	return retval;
+}
+
+/**
+ *	aac_rkt_ioremap
+ *	@dev: device to ioremap
+ *	@size: mapping resize request
+ *
+ */
+static int aac_rkt_ioremap(struct aac_dev * dev, u32 size)
+{
+	if (!size) {
+		iounmap(dev->regs.rkt);
+		return 0;
+	}
+	dev->base = dev->regs.rkt = ioremap(dev->base_start, size);
+	if (dev->base == NULL)
+		return -1;
+	dev->IndexRegs = &dev->regs.rkt->IndexRegs;
+	return 0;
+}
+
+/**
+ *	aac_rkt_init	-	initialize an i960 based AAC card
+ *	@dev: device to configure
+ *
+ *	Allocate and set up resources for the i960 based AAC variants. The
+ *	device_interface in the commregion will be allocated and linked
+ *	to the comm region.
+ */
+
+int aac_rkt_init(struct aac_dev *dev)
+{
+	/*
+	 *	Fill in the function dispatch table.
+	 */
+	dev->a_ops.adapter_ioremap = aac_rkt_ioremap;
+	dev->a_ops.adapter_comm = aac_rkt_select_comm;
+
+	return _aac_rx_init(dev);
+}