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, 33 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h
new file mode 100644
index 000000000..f3742bcc7
--- /dev/null
+++ b/drivers/char/tpm/tpm-dev.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TPM_DEV_H
+#define _TPM_DEV_H
+
+#include <linux/poll.h>
+#include "tpm.h"
+
+struct file_priv {
+	struct tpm_chip *chip;
+	struct tpm_space *space;
+
+	struct mutex buffer_mutex;
+	struct timer_list user_read_timer;      /* user needs to claim result */
+	struct work_struct timeout_work;
+	struct work_struct async_work;
+	wait_queue_head_t async_wait;
+	ssize_t response_length;
+	bool response_read;
+	bool command_enqueued;
+
+	u8 data_buffer[TPM_BUFSIZE];
+};
+
+void tpm_common_open(struct file *file, struct tpm_chip *chip,
+		     struct file_priv *priv, struct tpm_space *space);
+ssize_t tpm_common_read(struct file *file, char __user *buf,
+			size_t size, loff_t *off);
+ssize_t tpm_common_write(struct file *file, const char __user *buf,
+			 size_t size, loff_t *off);
+__poll_t tpm_common_poll(struct file *file, poll_table *wait);
+
+void tpm_common_release(struct file *file, struct file_priv *priv);
+#endif