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, 312 insertions, 0 deletions

diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
new file mode 100644
index 000000000..f0f8a4f57
--- /dev/null
+++ b/fs/jffs2/acl.c
@@ -0,0 +1,312 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/crc32.h>
+#include <linux/jffs2.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/mtd/mtd.h>
+#include "nodelist.h"
+
+static size_t jffs2_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(struct jffs2_acl_header)
+		       + count * sizeof(struct jffs2_acl_entry_short);
+	} else {
+		return sizeof(struct jffs2_acl_header)
+		       + 4 * sizeof(struct jffs2_acl_entry_short)
+		       + (count - 4) * sizeof(struct jffs2_acl_entry);
+	}
+}
+
+static int jffs2_acl_count(size_t size)
+{
+	size_t s;
+
+	size -= sizeof(struct jffs2_acl_header);
+	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
+		if (size % sizeof(struct jffs2_acl_entry_short))
+			return -1;
+		return size / sizeof(struct jffs2_acl_entry_short);
+	} else {
+		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
+		if (s % sizeof(struct jffs2_acl_entry))
+			return -1;
+		return s / sizeof(struct jffs2_acl_entry) + 4;
+	}
+}
+
+static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
+{
+	void *end = value + size;
+	struct jffs2_acl_header *header = value;
+	struct jffs2_acl_entry *entry;
+	struct posix_acl *acl;
+	uint32_t ver;
+	int i, count;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(struct jffs2_acl_header))
+		return ERR_PTR(-EINVAL);
+	ver = je32_to_cpu(header->a_version);
+	if (ver != JFFS2_ACL_VERSION) {
+		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
+		return ERR_PTR(-EINVAL);
+	}
+
+	value += sizeof(struct jffs2_acl_header);
+	count = jffs2_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	for (i=0; i < count; i++) {
+		entry = value;
+		if (value + sizeof(struct jffs2_acl_entry_short) > end)
+			goto fail;
+		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
+		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
+		switch (acl->a_entries[i].e_tag) {
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				value += sizeof(struct jffs2_acl_entry_short);
+				break;
+
+			case ACL_USER:
+				value += sizeof(struct jffs2_acl_entry);
+				if (value > end)
+					goto fail;
+				acl->a_entries[i].e_uid =
+					make_kuid(&init_user_ns,
+						  je32_to_cpu(entry->e_id));
+				break;
+			case ACL_GROUP:
+				value += sizeof(struct jffs2_acl_entry);
+				if (value > end)
+					goto fail;
+				acl->a_entries[i].e_gid =
+					make_kgid(&init_user_ns,
+						  je32_to_cpu(entry->e_id));
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	if (value != end)
+		goto fail;
+	return acl;
+ fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
+{
+	struct jffs2_acl_header *header;
+	struct jffs2_acl_entry *entry;
+	void *e;
+	size_t i;
+
+	*size = jffs2_acl_size(acl->a_count);
+	header = kmalloc_flex(*header, a_entries, acl->a_count);
+	if (!header)
+		return ERR_PTR(-ENOMEM);
+	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
+	e = header + 1;
+	for (i=0; i < acl->a_count; i++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[i];
+		entry = e;
+		entry->e_tag = cpu_to_je16(acl_e->e_tag);
+		entry->e_perm = cpu_to_je16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
+			case ACL_USER:
+				entry->e_id = cpu_to_je32(
+					from_kuid(&init_user_ns, acl_e->e_uid));
+				e += sizeof(struct jffs2_acl_entry);
+				break;
+			case ACL_GROUP:
+				entry->e_id = cpu_to_je32(
+					from_kgid(&init_user_ns, acl_e->e_gid));
+				e += sizeof(struct jffs2_acl_entry);
+				break;
+
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				e += sizeof(struct jffs2_acl_entry_short);
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	return header;
+ fail:
+	kfree(header);
+	return ERR_PTR(-EINVAL);
+}
+
+struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu)
+{
+	struct posix_acl *acl;
+	char *value = NULL;
+	int rc, xprefix;
+
+	if (rcu)
+		return ERR_PTR(-ECHILD);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
+	if (rc > 0) {
+		value = kmalloc(rc, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
+	}
+	if (rc > 0) {
+		acl = jffs2_acl_from_medium(value, rc);
+	} else if (rc == -ENODATA || rc == -ENOSYS) {
+		acl = NULL;
+	} else {
+		acl = ERR_PTR(rc);
+	}
+	kfree(value);
+	return acl;
+}
+
+static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
+{
+	char *value = NULL;
+	size_t size = 0;
+	int rc;
+
+	if (acl) {
+		value = jffs2_acl_to_medium(acl, &size);
+		if (IS_ERR(value))
+			return PTR_ERR(value);
+	}
+	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
+	if (!value && rc == -ENODATA)
+		rc = 0;
+	kfree(value);
+
+	return rc;
+}
+
+int jffs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct posix_acl *acl, int type)
+{
+	int rc, xprefix;
+	struct inode *inode = d_inode(dentry);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
+		if (acl) {
+			umode_t mode;
+
+			rc = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode,
+						   &acl);
+			if (rc)
+				return rc;
+			if (inode->i_mode != mode) {
+				struct iattr attr;
+
+				attr.ia_valid = ATTR_MODE | ATTR_CTIME;
+				attr.ia_mode = mode;
+				attr.ia_ctime = current_time(inode);
+				rc = jffs2_do_setattr(inode, &attr);
+				if (rc < 0)
+					return rc;
+			}
+		}
+		break;
+	case ACL_TYPE_DEFAULT:
+		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+	rc = __jffs2_set_acl(inode, xprefix, acl);
+	if (!rc)
+		set_cached_acl(inode, type, acl);
+	return rc;
+}
+
+int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
+{
+	struct posix_acl *default_acl, *acl;
+	int rc;
+
+	cache_no_acl(inode);
+
+	rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
+	if (rc)
+		return rc;
+
+	if (default_acl) {
+		set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
+		posix_acl_release(default_acl);
+	}
+	if (acl) {
+		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+		posix_acl_release(acl);
+	}
+	return 0;
+}
+
+int jffs2_init_acl_post(struct inode *inode)
+{
+	int rc;
+
+	if (inode->i_default_acl) {
+		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
+		if (rc)
+			return rc;
+	}
+
+	if (inode->i_acl) {
+		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}