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, 237 insertions, 0 deletions

diff --git a/fs/afs/main.c b/fs/afs/main.c
new file mode 100644
index 000000000..7a883c599
--- /dev/null
+++ b/fs/afs/main.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS client file system
+ *
+ * Copyright (C) 2002,5 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/sched.h>
+#include <linux/random.h>
+#include <linux/proc_fs.h>
+#define CREATE_TRACE_POINTS
+#include "internal.h"
+
+MODULE_DESCRIPTION("AFS Client File System");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+unsigned afs_debug;
+module_param_named(debug, afs_debug, uint, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(debug, "AFS debugging mask");
+
+static char *rootcell;
+
+module_param(rootcell, charp, 0);
+MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list");
+
+struct workqueue_struct *afs_wq;
+static struct proc_dir_entry *afs_proc_symlink;
+
+#if defined(CONFIG_ALPHA)
+const char afs_init_sysname[] = "alpha_linux26";
+#elif defined(CONFIG_X86_64)
+const char afs_init_sysname[] = "amd64_linux26";
+#elif defined(CONFIG_ARM)
+const char afs_init_sysname[] = "arm_linux26";
+#elif defined(CONFIG_ARM64)
+const char afs_init_sysname[] = "aarch64_linux26";
+#elif defined(CONFIG_X86_32)
+const char afs_init_sysname[] = "i386_linux26";
+#elif defined(CONFIG_PPC64)
+const char afs_init_sysname[] = "ppc64_linux26";
+#elif defined(CONFIG_PPC32)
+const char afs_init_sysname[] = "ppc_linux26";
+#elif defined(CONFIG_S390)
+#ifdef CONFIG_64BIT
+const char afs_init_sysname[] = "s390x_linux26";
+#else
+const char afs_init_sysname[] = "s390_linux26";
+#endif
+#elif defined(CONFIG_SPARC64)
+const char afs_init_sysname[] = "sparc64_linux26";
+#elif defined(CONFIG_SPARC32)
+const char afs_init_sysname[] = "sparc_linux26";
+#else
+const char afs_init_sysname[] = "unknown_linux26";
+#endif
+
+/*
+ * Initialise an AFS network namespace record.
+ */
+static int __net_init afs_net_init(struct net *net_ns)
+{
+	struct afs_sysnames *sysnames;
+	struct afs_net *net = afs_net(net_ns);
+	int ret;
+
+	net->net = net_ns;
+	net->live = true;
+	generate_random_uuid((unsigned char *)&net->uuid);
+
+	INIT_WORK(&net->charge_preallocation_work, afs_charge_preallocation);
+	INIT_WORK(&net->rx_oob_work, afs_process_oob_queue);
+	mutex_init(&net->socket_mutex);
+
+	net->cells = RB_ROOT;
+	idr_init(&net->cells_dyn_ino);
+	init_rwsem(&net->cells_lock);
+	mutex_init(&net->cells_alias_lock);
+	mutex_init(&net->proc_cells_lock);
+	INIT_HLIST_HEAD(&net->proc_cells);
+
+	seqlock_init(&net->fs_lock);
+	INIT_LIST_HEAD(&net->fs_probe_fast);
+	INIT_LIST_HEAD(&net->fs_probe_slow);
+	INIT_HLIST_HEAD(&net->fs_proc);
+
+	INIT_WORK(&net->fs_prober, afs_fs_probe_dispatcher);
+	timer_setup(&net->fs_probe_timer, afs_fs_probe_timer, 0);
+	atomic_set(&net->servers_outstanding, 1);
+
+	ret = -ENOMEM;
+	sysnames = kzalloc_obj(*sysnames);
+	if (!sysnames)
+		goto error_sysnames;
+	sysnames->subs[0] = (char *)&afs_init_sysname;
+	sysnames->nr = 1;
+	refcount_set(&sysnames->usage, 1);
+	net->sysnames = sysnames;
+	rwlock_init(&net->sysnames_lock);
+
+	/* Register the /proc stuff */
+	ret = afs_proc_init(net);
+	if (ret < 0)
+		goto error_proc;
+
+	/* Initialise the cell DB */
+	ret = afs_cell_init(net, rootcell);
+	if (ret < 0)
+		goto error_cell_init;
+
+	/* Create the RxRPC transport */
+	ret = afs_open_socket(net);
+	if (ret < 0)
+		goto error_open_socket;
+
+	return 0;
+
+error_open_socket:
+	net->live = false;
+	afs_fs_probe_cleanup(net);
+	afs_cell_purge(net);
+	afs_wait_for_servers(net);
+error_cell_init:
+	net->live = false;
+	afs_proc_cleanup(net);
+error_proc:
+	afs_put_sysnames(net->sysnames);
+error_sysnames:
+	idr_destroy(&net->cells_dyn_ino);
+	net->live = false;
+	return ret;
+}
+
+/*
+ * Clean up and destroy an AFS network namespace record.
+ */
+static void __net_exit afs_net_exit(struct net *net_ns)
+{
+	struct afs_net *net = afs_net(net_ns);
+
+	net->live = false;
+	afs_fs_probe_cleanup(net);
+	afs_cell_purge(net);
+	afs_wait_for_servers(net);
+	afs_close_socket(net);
+	afs_proc_cleanup(net);
+	afs_put_sysnames(net->sysnames);
+	idr_destroy(&net->cells_dyn_ino);
+	kfree_rcu(rcu_access_pointer(net->address_prefs), rcu);
+}
+
+static struct pernet_operations afs_net_ops = {
+	.init	= afs_net_init,
+	.exit	= afs_net_exit,
+	.id	= &afs_net_id,
+	.size	= sizeof(struct afs_net),
+};
+
+/*
+ * initialise the AFS client FS module
+ */
+static int __init afs_init(void)
+{
+	int ret = -ENOMEM;
+
+	printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 registering.\n");
+
+	afs_wq = alloc_workqueue("afs", WQ_PERCPU, 0);
+	if (!afs_wq)
+		goto error_afs_wq;
+	afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+	if (!afs_async_calls)
+		goto error_async;
+	afs_lock_manager = alloc_workqueue("kafs_lockd", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
+	if (!afs_lock_manager)
+		goto error_lockmgr;
+
+	ret = register_pernet_device(&afs_net_ops);
+	if (ret < 0)
+		goto error_net;
+
+	/* register the filesystems */
+	ret = afs_fs_init();
+	if (ret < 0)
+		goto error_fs;
+
+	afs_proc_symlink = proc_symlink("fs/afs", NULL, "../self/net/afs");
+	if (!afs_proc_symlink) {
+		ret = -ENOMEM;
+		goto error_proc;
+	}
+
+	return ret;
+
+error_proc:
+	afs_fs_exit();
+error_fs:
+	unregister_pernet_device(&afs_net_ops);
+error_net:
+	destroy_workqueue(afs_lock_manager);
+error_lockmgr:
+	destroy_workqueue(afs_async_calls);
+error_async:
+	destroy_workqueue(afs_wq);
+error_afs_wq:
+	rcu_barrier();
+	printk(KERN_ERR "kAFS: failed to register: %d\n", ret);
+	return ret;
+}
+
+/* XXX late_initcall is kludgy, but the only alternative seems to create
+ * a transport upon the first mount, which is worse. Or is it?
+ */
+late_initcall(afs_init);	/* must be called after net/ to create socket */
+
+/*
+ * clean up on module removal
+ */
+static void __exit afs_exit(void)
+{
+	printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 unregistering.\n");
+
+	proc_remove(afs_proc_symlink);
+	afs_fs_exit();
+	unregister_pernet_device(&afs_net_ops);
+	destroy_workqueue(afs_lock_manager);
+	destroy_workqueue(afs_async_calls);
+	destroy_workqueue(afs_wq);
+	afs_clean_up_permit_cache();
+	rcu_barrier();
+}
+
+module_exit(afs_exit);