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, 332 insertions, 0 deletions

diff --git a/drivers/nvme/target/debugfs.c b/drivers/nvme/target/debugfs.c
new file mode 100644
index 000000000..e85fe1d4c
--- /dev/null
+++ b/drivers/nvme/target/debugfs.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DebugFS interface for the NVMe target.
+ * Copyright (c) 2022-2024 Shadow
+ * Copyright (c) 2024 SUSE LLC
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+#include "nvmet.h"
+#include "debugfs.h"
+
+static struct dentry *nvmet_debugfs;
+
+#define NVMET_DEBUGFS_ATTR(field) \
+	static int field##_open(struct inode *inode, struct file *file) \
+	{ return single_open(file, field##_show, inode->i_private); } \
+	\
+	static const struct file_operations field##_fops = { \
+		.open = field##_open, \
+		.read = seq_read, \
+		.release = single_release, \
+	}
+
+#define NVMET_DEBUGFS_RW_ATTR(field) \
+	static int field##_open(struct inode *inode, struct file *file) \
+	{ return single_open(file, field##_show, inode->i_private); } \
+	\
+	static const struct file_operations field##_fops = { \
+		.open = field##_open, \
+		.read = seq_read, \
+		.write = field##_write, \
+		.release = single_release, \
+	}
+
+static int nvmet_ctrl_hostnqn_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+
+	seq_puts(m, ctrl->hostnqn);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_hostnqn);
+
+static int nvmet_ctrl_kato_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+
+	seq_printf(m, "%d\n", ctrl->kato);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_kato);
+
+static int nvmet_ctrl_port_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+
+	seq_printf(m, "%d\n", le16_to_cpu(ctrl->port->disc_addr.portid));
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_port);
+
+static const char *const csts_state_names[] = {
+	[NVME_CSTS_RDY]		= "ready",
+	[NVME_CSTS_CFS]		= "fatal",
+	[NVME_CSTS_NSSRO]	= "reset",
+	[NVME_CSTS_SHST_OCCUR]	= "shutdown",
+	[NVME_CSTS_SHST_CMPLT]	= "completed",
+	[NVME_CSTS_PP]		= "paused",
+};
+
+static int nvmet_ctrl_state_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+	bool sep = false;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(csts_state_names); i++) {
+		int state = BIT(i);
+
+		if (!(ctrl->csts & state))
+			continue;
+		if (sep)
+			seq_puts(m, "|");
+		sep = true;
+		if (csts_state_names[state])
+			seq_puts(m, csts_state_names[state]);
+		else
+			seq_printf(m, "%d", state);
+	}
+	if (sep)
+		seq_printf(m, "\n");
+	return 0;
+}
+
+static ssize_t nvmet_ctrl_state_write(struct file *file, const char __user *buf,
+				      size_t count, loff_t *ppos)
+{
+	struct seq_file *m = file->private_data;
+	struct nvmet_ctrl *ctrl = m->private;
+	char reset[16];
+
+	if (count >= sizeof(reset))
+		return -EINVAL;
+	if (copy_from_user(reset, buf, count))
+		return -EFAULT;
+	if (!memcmp(reset, "fatal", 5))
+		nvmet_ctrl_fatal_error(ctrl);
+	else
+		return -EINVAL;
+	return count;
+}
+NVMET_DEBUGFS_RW_ATTR(nvmet_ctrl_state);
+
+static int nvmet_ctrl_host_traddr_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+	ssize_t size;
+	char buf[NVMF_TRADDR_SIZE + 1];
+
+	size = nvmet_ctrl_host_traddr(ctrl, buf, NVMF_TRADDR_SIZE);
+	if (size < 0) {
+		buf[0] = '\0';
+		size = 0;
+	}
+	buf[size] = '\0';
+	seq_printf(m, "%s\n", buf);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_host_traddr);
+
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+static int nvmet_ctrl_tls_key_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+	key_serial_t keyid = nvmet_queue_tls_keyid(ctrl->sqs[0]);
+
+	seq_printf(m, "%08x\n", keyid);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_tls_key);
+
+static int nvmet_ctrl_tls_concat_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+
+	seq_printf(m, "%d\n", ctrl->concat);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_tls_concat);
+#endif
+
+static const char *const nvmet_pr_type_names[] = {
+	[NVME_PR_WRITE_EXCLUSIVE]		= "write_exclusive",
+	[NVME_PR_EXCLUSIVE_ACCESS]		= "exclusive_access",
+	[NVME_PR_WRITE_EXCLUSIVE_REG_ONLY]	= "write_exclusive_reg_only",
+	[NVME_PR_EXCLUSIVE_ACCESS_REG_ONLY]	= "exclusive_access_reg_only",
+	[NVME_PR_WRITE_EXCLUSIVE_ALL_REGS]	= "write_exclusive_all_regs",
+	[NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS]	= "exclusive_access_all_regs",
+};
+
+static const char *nvmet_pr_type_to_str(enum nvme_pr_type type)
+{
+	if (type < ARRAY_SIZE(nvmet_pr_type_names) &&
+	    nvmet_pr_type_names[type])
+		return nvmet_pr_type_names[type];
+	return "unknown";
+}
+
+static const char *const nvmet_pr_notify_names[] = {
+	[NVME_PR_NOTIFY_BIT_REG_PREEMPTED]	= "reg_preempted",
+	[NVME_PR_NOTIFY_BIT_RESV_RELEASED]	= "resv_released",
+	[NVME_PR_NOTIFY_BIT_RESV_PREEMPTED]	= "resv_preempted",
+};
+
+static void nvmet_pr_notify_mask_to_str(struct seq_file *m, unsigned long mask)
+{
+	bool sep = false;
+	int i;
+
+	if (!mask) {
+		seq_puts(m, "none");
+		return;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(nvmet_pr_notify_names); i++) {
+		if (!test_bit(i, &mask) || !nvmet_pr_notify_names[i])
+			continue;
+		if (sep)
+			seq_putc(m, ',');
+		seq_puts(m, nvmet_pr_notify_names[i]);
+		sep = true;
+	}
+}
+
+static int nvmet_ns_pr_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ns *ns = m->private;
+	struct nvmet_pr *pr = &ns->pr;
+	struct nvmet_pr_registrant *holder, *reg;
+
+	seq_printf(m, "enable=%d\n", pr->enable);
+	if (!pr->enable)
+		return 0;
+
+	seq_printf(m, "generation=%u\n", atomic_read(&pr->generation));
+	seq_puts(m, "notify_mask=");
+	nvmet_pr_notify_mask_to_str(m, pr->notify_mask);
+	seq_putc(m, '\n');
+
+	rcu_read_lock();
+	holder = rcu_dereference(pr->holder);
+	if (holder) {
+		seq_printf(m, "rtype=%s\n",
+			   nvmet_pr_type_to_str(holder->rtype));
+		seq_printf(m, "holder=%pUb,0x%llx\n",
+			   &holder->hostid, holder->rkey);
+	} else {
+		seq_puts(m, "rtype=none\n");
+		seq_puts(m, "holder=none\n");
+	}
+
+	list_for_each_entry_rcu(reg, &pr->registrant_list, entry) {
+		seq_printf(m, "reg=%pUb,0x%llx\n",
+			   &reg->hostid, reg->rkey);
+	}
+	rcu_read_unlock();
+
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ns_pr);
+
+void nvmet_debugfs_ns_setup(struct nvmet_ns *ns)
+{
+	char name[16];
+	struct dentry *parent = ns->subsys->debugfs_dir;
+
+	if (!parent)
+		return;
+	snprintf(name, sizeof(name), "ns%u", ns->nsid);
+	ns->debugfs_dir = debugfs_create_dir(name, parent);
+	if (IS_ERR(ns->debugfs_dir)) {
+		ns->debugfs_dir = NULL;
+		return;
+	}
+	debugfs_create_file("reservation", 0400, ns->debugfs_dir, ns,
+			    &nvmet_ns_pr_fops);
+}
+
+void nvmet_debugfs_ns_free(struct nvmet_ns *ns)
+{
+	debugfs_remove_recursive(ns->debugfs_dir);
+	ns->debugfs_dir = NULL;
+}
+
+int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl)
+{
+	char name[32];
+	struct dentry *parent = ctrl->subsys->debugfs_dir;
+	int ret;
+
+	if (!parent)
+		return -ENODEV;
+	snprintf(name, sizeof(name), "ctrl%d", ctrl->cntlid);
+	ctrl->debugfs_dir = debugfs_create_dir(name, parent);
+	if (IS_ERR(ctrl->debugfs_dir)) {
+		ret = PTR_ERR(ctrl->debugfs_dir);
+		ctrl->debugfs_dir = NULL;
+		return ret;
+	}
+	debugfs_create_file("port", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_port_fops);
+	debugfs_create_file("hostnqn", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_hostnqn_fops);
+	debugfs_create_file("kato", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_kato_fops);
+	debugfs_create_file("state", S_IRUSR | S_IWUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_state_fops);
+	debugfs_create_file("host_traddr", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_host_traddr_fops);
+#ifdef CONFIG_NVME_TARGET_TCP_TLS
+	debugfs_create_file("tls_concat", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_tls_concat_fops);
+	debugfs_create_file("tls_key", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_tls_key_fops);
+#endif
+	return 0;
+}
+
+void nvmet_debugfs_ctrl_free(struct nvmet_ctrl *ctrl)
+{
+	debugfs_remove_recursive(ctrl->debugfs_dir);
+}
+
+int nvmet_debugfs_subsys_setup(struct nvmet_subsys *subsys)
+{
+	int ret = 0;
+
+	subsys->debugfs_dir = debugfs_create_dir(subsys->subsysnqn,
+						 nvmet_debugfs);
+	if (IS_ERR(subsys->debugfs_dir)) {
+		ret = PTR_ERR(subsys->debugfs_dir);
+		subsys->debugfs_dir = NULL;
+	}
+	return ret;
+}
+
+void nvmet_debugfs_subsys_free(struct nvmet_subsys *subsys)
+{
+	debugfs_remove_recursive(subsys->debugfs_dir);
+}
+
+int __init nvmet_init_debugfs(void)
+{
+	struct dentry *parent;
+
+	parent = debugfs_create_dir("nvmet", NULL);
+	if (IS_ERR(parent)) {
+		pr_warn("%s: failed to create debugfs directory\n", "nvmet");
+		return PTR_ERR(parent);
+	}
+	nvmet_debugfs = parent;
+	return 0;
+}
+
+void nvmet_exit_debugfs(void)
+{
+	debugfs_remove_recursive(nvmet_debugfs);
+}