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, 71 insertions, 0 deletions

diff --git a/security/integrity/iint.c b/security/integrity/iint.c
new file mode 100644
index 000000000..8ec1a3436
--- /dev/null
+++ b/security/integrity/iint.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 IBM Corporation
+ *
+ * Authors:
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * File: integrity_iint.c
+ *	- initialize the integrity directory in securityfs
+ *	- load IMA and EVM keys
+ */
+#include <linux/security.h>
+#include "integrity.h"
+
+struct dentry *integrity_dir;
+
+/*
+ * integrity_kernel_read - read data from the file
+ *
+ * This is a function for reading file content instead of kernel_read().
+ * It does not perform locking checks to ensure it cannot be blocked.
+ * It does not perform security checks because it is irrelevant for IMA.
+ *
+ */
+int integrity_kernel_read(struct file *file, loff_t offset,
+			  void *addr, unsigned long count)
+{
+	return __kernel_read(file, addr, count, &offset);
+}
+
+/*
+ * integrity_load_keys - load integrity keys hook
+ *
+ * Hooks is called from init/main.c:kernel_init_freeable()
+ * when rootfs is ready
+ */
+void __init integrity_load_keys(void)
+{
+	ima_load_x509();
+
+	if (!IS_ENABLED(CONFIG_IMA_LOAD_X509))
+		evm_load_x509();
+}
+
+int __init integrity_fs_init(void)
+{
+	if (integrity_dir)
+		return 0;
+
+	integrity_dir = securityfs_create_dir("integrity", NULL);
+	if (IS_ERR(integrity_dir)) {
+		int ret = PTR_ERR(integrity_dir);
+
+		if (ret != -ENODEV)
+			pr_err("Unable to create integrity sysfs dir: %d\n",
+			       ret);
+		integrity_dir = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+
+void __init integrity_fs_fini(void)
+{
+	if (!integrity_dir || !simple_empty(integrity_dir))
+		return;
+
+	securityfs_remove(integrity_dir);
+	integrity_dir = NULL;
+}