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, 168 insertions, 0 deletions

diff --git a/drivers/edac/edac_module.c b/drivers/edac/edac_module.c
new file mode 100644
index 000000000..1c9f62382
--- /dev/null
+++ b/drivers/edac/edac_module.c
@@ -0,0 +1,168 @@
+/*
+ * edac_module.c
+ *
+ * (C) 2007 www.softwarebitmaker.com
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * Author: Doug Thompson <dougthompson@xmission.com>
+ *
+ */
+#include <linux/edac.h>
+
+#include "edac_mc.h"
+#include "edac_module.h"
+
+#define EDAC_VERSION "Ver: 3.0.0"
+
+#ifdef CONFIG_EDAC_DEBUG
+
+static int edac_set_debug_level(const char *buf,
+				const struct kernel_param *kp)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > 4)
+		return -EINVAL;
+
+	return param_set_int(buf, kp);
+}
+
+/* Values of 0 to 4 will generate output */
+int edac_debug_level = 2;
+EXPORT_SYMBOL_GPL(edac_debug_level);
+
+module_param_call(edac_debug_level, edac_set_debug_level, param_get_int,
+		  &edac_debug_level, 0644);
+MODULE_PARM_DESC(edac_debug_level, "EDAC debug level: [0-4], default: 2");
+#endif
+
+/*
+ * edac_op_state_to_string()
+ */
+char *edac_op_state_to_string(int opstate)
+{
+	if (opstate == OP_RUNNING_POLL)
+		return "POLLED";
+	else if (opstate == OP_RUNNING_INTERRUPT)
+		return "INTERRUPT";
+	else if (opstate == OP_RUNNING_POLL_INTR)
+		return "POLL-INTR";
+	else if (opstate == OP_ALLOC)
+		return "ALLOC";
+	else if (opstate == OP_OFFLINE)
+		return "OFFLINE";
+
+	return "UNKNOWN";
+}
+
+/*
+ * sysfs object: /sys/devices/system/edac
+ *	need to export to other files
+ */
+static const struct bus_type edac_subsys = {
+	.name = "edac",
+	.dev_name = "edac",
+};
+
+static int edac_subsys_init(void)
+{
+	int err;
+
+	/* create the /sys/devices/system/edac directory */
+	err = subsys_system_register(&edac_subsys, NULL);
+	if (err)
+		printk(KERN_ERR "Error registering toplevel EDAC sysfs dir\n");
+
+	return err;
+}
+
+static void edac_subsys_exit(void)
+{
+	bus_unregister(&edac_subsys);
+}
+
+/* return pointer to the 'edac' node in sysfs */
+const struct bus_type *edac_get_sysfs_subsys(void)
+{
+	return &edac_subsys;
+}
+EXPORT_SYMBOL_GPL(edac_get_sysfs_subsys);
+/*
+ * edac_init
+ *      module initialization entry point
+ */
+static int __init edac_init(void)
+{
+	int err = 0;
+
+	edac_printk(KERN_INFO, EDAC_MC, EDAC_VERSION "\n");
+
+	err = edac_subsys_init();
+	if (err)
+		return err;
+
+	/*
+	 * Harvest and clear any boot/initialization PCI parity errors
+	 *
+	 * FIXME: This only clears errors logged by devices present at time of
+	 *      module initialization.  We should also do an initial clear
+	 *      of each newly hotplugged device.
+	 */
+	edac_pci_clear_parity_errors();
+
+	err = edac_mc_sysfs_init();
+	if (err)
+		goto err_sysfs;
+
+	edac_debugfs_init();
+
+	err = edac_workqueue_setup();
+	if (err) {
+		edac_printk(KERN_ERR, EDAC_MC, "Failure initializing workqueue\n");
+		goto err_wq;
+	}
+
+	return 0;
+
+err_wq:
+	edac_debugfs_exit();
+	edac_mc_sysfs_exit();
+
+err_sysfs:
+	edac_subsys_exit();
+
+	return err;
+}
+
+/*
+ * edac_exit()
+ *      module exit/termination function
+ */
+static void __exit edac_exit(void)
+{
+	edac_dbg(0, "\n");
+
+	/* tear down the various subsystems */
+	edac_workqueue_teardown();
+	edac_mc_sysfs_exit();
+	edac_debugfs_exit();
+	edac_subsys_exit();
+}
+
+/*
+ * Inform the kernel of our entry and exit points
+ */
+subsys_initcall(edac_init);
+module_exit(edac_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Doug Thompson www.softwarebitmaker.com, et al");
+MODULE_DESCRIPTION("Core library routines for EDAC reporting");