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, 286 insertions, 0 deletions

diff --git a/drivers/pnp/pnpbios/proc.c b/drivers/pnp/pnpbios/proc.c
new file mode 100644
index 000000000..0f0d819b1
--- /dev/null
+++ b/drivers/pnp/pnpbios/proc.c
@@ -0,0 +1,286 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/bus/pnp interface for Plug and Play devices
+ *
+ * Written by David Hinds, dahinds@users.sourceforge.net
+ * Modified by Thomas Hood
+ *
+ * The .../devices and .../<node> and .../boot/<node> files are
+ * utilized by the lspnp and setpnp utilities, supplied with the
+ * pcmcia-cs package.
+ *     http://pcmcia-cs.sourceforge.net
+ *
+ * The .../escd file is utilized by the lsescd utility written by
+ * Gunther Mayer.
+ *
+ * The .../legacy_device_resources file is not used yet.
+ *
+ * The other files are human-readable.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/proc_fs.h>
+#include <linux/pnp.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+
+#include "pnpbios.h"
+
+static struct proc_dir_entry *proc_pnp = NULL;
+static struct proc_dir_entry *proc_pnp_boot = NULL;
+
+static int pnpconfig_proc_show(struct seq_file *m, void *v)
+{
+	struct pnp_isa_config_struc pnps;
+
+	if (pnp_bios_isapnp_config(&pnps))
+		return -EIO;
+	seq_printf(m, "structure_revision %d\n"
+		      "number_of_CSNs %d\n"
+		      "ISA_read_data_port 0x%x\n",
+		   pnps.revision, pnps.no_csns, pnps.isa_rd_data_port);
+	return 0;
+}
+
+static int escd_info_proc_show(struct seq_file *m, void *v)
+{
+	struct escd_info_struc escd;
+
+	if (pnp_bios_escd_info(&escd))
+		return -EIO;
+	seq_printf(m, "min_ESCD_write_size %d\n"
+			"ESCD_size %d\n"
+			"NVRAM_base 0x%x\n",
+			escd.min_escd_write_size,
+			escd.escd_size, escd.nv_storage_base);
+	return 0;
+}
+
+#define MAX_SANE_ESCD_SIZE (32*1024)
+static int escd_proc_show(struct seq_file *m, void *v)
+{
+	struct escd_info_struc escd;
+	char *tmpbuf;
+	int escd_size;
+
+	if (pnp_bios_escd_info(&escd))
+		return -EIO;
+
+	/* sanity check */
+	if (escd.escd_size > MAX_SANE_ESCD_SIZE) {
+		printk(KERN_ERR
+		       "PnPBIOS: %s: ESCD size reported by BIOS escd_info call is too great\n", __func__);
+		return -EFBIG;
+	}
+
+	tmpbuf = kzalloc(escd.escd_size, GFP_KERNEL);
+	if (!tmpbuf)
+		return -ENOMEM;
+
+	if (pnp_bios_read_escd(tmpbuf, escd.nv_storage_base)) {
+		kfree(tmpbuf);
+		return -EIO;
+	}
+
+	escd_size =
+	    (unsigned char)(tmpbuf[0]) + (unsigned char)(tmpbuf[1]) * 256;
+
+	/* sanity check */
+	if (escd_size > MAX_SANE_ESCD_SIZE) {
+		printk(KERN_ERR "PnPBIOS: %s: ESCD size reported by"
+				" BIOS read_escd call is too great\n", __func__);
+		kfree(tmpbuf);
+		return -EFBIG;
+	}
+
+	seq_write(m, tmpbuf, escd_size);
+	kfree(tmpbuf);
+	return 0;
+}
+
+static int pnp_legacyres_proc_show(struct seq_file *m, void *v)
+{
+	void *buf;
+
+	buf = kmalloc(65536, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	if (pnp_bios_get_stat_res(buf)) {
+		kfree(buf);
+		return -EIO;
+	}
+
+	seq_write(m, buf, 65536);
+	kfree(buf);
+	return 0;
+}
+
+static int pnp_devices_proc_show(struct seq_file *m, void *v)
+{
+	struct pnp_bios_node *node;
+	u8 nodenum;
+
+	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+
+	for (nodenum = 0; nodenum < 0xff;) {
+		u8 thisnodenum = nodenum;
+
+		if (pnp_bios_get_dev_node(&nodenum, PNPMODE_DYNAMIC, node))
+			break;
+		seq_printf(m, "%02x\t%08x\t%3phC\t%04x\n",
+			     node->handle, node->eisa_id,
+			     node->type_code, node->flags);
+		if (nodenum <= thisnodenum) {
+			printk(KERN_ERR
+			       "%s Node number 0x%x is out of sequence following node 0x%x. Aborting.\n",
+			       "PnPBIOS: proc_read_devices:",
+			       (unsigned int)nodenum,
+			       (unsigned int)thisnodenum);
+			break;
+		}
+	}
+	kfree(node);
+	return 0;
+}
+
+static int pnpbios_proc_show(struct seq_file *m, void *v)
+{
+	void *data = m->private;
+	struct pnp_bios_node *node;
+	int boot = (long)data >> 8;
+	u8 nodenum = (long)data;
+	int len;
+
+	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+	if (pnp_bios_get_dev_node(&nodenum, boot, node)) {
+		kfree(node);
+		return -EIO;
+	}
+	len = node->size - sizeof(struct pnp_bios_node);
+	seq_write(m, node->data, len);
+	kfree(node);
+	return 0;
+}
+
+static int pnpbios_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pnpbios_proc_show, pde_data(inode));
+}
+
+static ssize_t pnpbios_proc_write(struct file *file, const char __user *buf,
+				  size_t count, loff_t *pos)
+{
+	void *data = pde_data(file_inode(file));
+	struct pnp_bios_node *node;
+	int boot = (long)data >> 8;
+	u8 nodenum = (long)data;
+	int ret = count;
+
+	node = kzalloc(node_info.max_node_size, GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+	if (pnp_bios_get_dev_node(&nodenum, boot, node)) {
+		ret = -EIO;
+		goto out;
+	}
+	if (count != node->size - sizeof(struct pnp_bios_node)) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (copy_from_user(node->data, buf, count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	if (pnp_bios_set_dev_node(node->handle, boot, node) != 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = count;
+out:
+	kfree(node);
+	return ret;
+}
+
+static const struct proc_ops pnpbios_proc_ops = {
+	.proc_open	= pnpbios_proc_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+	.proc_write	= pnpbios_proc_write,
+};
+
+int pnpbios_interface_attach_device(struct pnp_bios_node *node)
+{
+	char name[3];
+
+	sprintf(name, "%02x", node->handle);
+
+	if (!proc_pnp)
+		return -EIO;
+	if (!pnpbios_dont_use_current_config) {
+		proc_create_data(name, 0644, proc_pnp, &pnpbios_proc_ops,
+				 (void *)(long)(node->handle));
+	}
+
+	if (!proc_pnp_boot)
+		return -EIO;
+	if (proc_create_data(name, 0644, proc_pnp_boot, &pnpbios_proc_ops,
+			     (void *)(long)(node->handle + 0x100)))
+		return 0;
+	return -EIO;
+}
+
+/*
+ * When this is called, pnpbios functions are assumed to
+ * work and the pnpbios_dont_use_current_config flag
+ * should already have been set to the appropriate value
+ */
+int __init pnpbios_proc_init(void)
+{
+	proc_pnp = proc_mkdir("bus/pnp", NULL);
+	if (!proc_pnp)
+		return -EIO;
+	proc_pnp_boot = proc_mkdir("boot", proc_pnp);
+	if (!proc_pnp_boot)
+		return -EIO;
+	proc_create_single("devices", 0, proc_pnp, pnp_devices_proc_show);
+	proc_create_single("configuration_info", 0, proc_pnp,
+			pnpconfig_proc_show);
+	proc_create_single("escd_info", 0, proc_pnp, escd_info_proc_show);
+	proc_create_single("escd", S_IRUSR, proc_pnp, escd_proc_show);
+	proc_create_single("legacy_device_resources", 0, proc_pnp,
+			pnp_legacyres_proc_show);
+	return 0;
+}
+
+void __exit pnpbios_proc_exit(void)
+{
+	int i;
+	char name[3];
+
+	if (!proc_pnp)
+		return;
+
+	for (i = 0; i < 0xff; i++) {
+		sprintf(name, "%02x", i);
+		if (!pnpbios_dont_use_current_config)
+			remove_proc_entry(name, proc_pnp);
+		remove_proc_entry(name, proc_pnp_boot);
+	}
+	remove_proc_entry("legacy_device_resources", proc_pnp);
+	remove_proc_entry("escd", proc_pnp);
+	remove_proc_entry("escd_info", proc_pnp);
+	remove_proc_entry("configuration_info", proc_pnp);
+	remove_proc_entry("devices", proc_pnp);
+	remove_proc_entry("boot", proc_pnp);
+	remove_proc_entry("bus/pnp", NULL);
+}