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, 259 insertions, 0 deletions

diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
new file mode 100644
index 000000000..85d3dd48b
--- /dev/null
+++ b/fs/ceph/acl.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/ceph/acl.c
+ *
+ * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
+ */
+
+#include <linux/ceph/ceph_debug.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+static inline void ceph_set_cached_acl(struct inode *inode,
+					int type, struct posix_acl *acl)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	spin_lock(&ci->i_ceph_lock);
+	if (__ceph_caps_issued_mask_metric(ci, CEPH_CAP_XATTR_SHARED, 0))
+		set_cached_acl(inode, type, acl);
+	else
+		forget_cached_acl(inode, type);
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+struct posix_acl *ceph_get_acl(struct inode *inode, int type, bool rcu)
+{
+	struct ceph_client *cl = ceph_inode_to_client(inode);
+	int size;
+	unsigned int retry_cnt = 0;
+	const char *name;
+	char *value = NULL;
+	struct posix_acl *acl;
+
+	if (rcu)
+		return ERR_PTR(-ECHILD);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+
+retry:
+	size = __ceph_getxattr(inode, name, "", 0);
+	if (size > 0) {
+		value = kzalloc(size, GFP_NOFS);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		size = __ceph_getxattr(inode, name, value, size);
+	}
+
+	if (size == -ERANGE && retry_cnt < 10) {
+		retry_cnt++;
+		kfree(value);
+		value = NULL;
+		goto retry;
+	}
+
+	if (size > 0) {
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+	} else if (size == -ENODATA || size == 0) {
+		acl = NULL;
+	} else {
+		pr_err_ratelimited_client(cl, "%llx.%llx failed, err=%d\n",
+					  ceph_vinop(inode), size);
+		acl = ERR_PTR(-EIO);
+	}
+
+	kfree(value);
+
+	if (!IS_ERR(acl))
+		ceph_set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+int ceph_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		 struct posix_acl *acl, int type)
+{
+	int ret = 0;
+	size_t size = 0;
+	const char *name = NULL;
+	char *value = NULL;
+	struct iattr newattrs;
+	struct inode *inode = d_inode(dentry);
+	struct timespec64 old_ctime = inode_get_ctime(inode);
+	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP) {
+		ret = -EROFS;
+		goto out;
+	}
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+		if (acl) {
+			ret = posix_acl_update_mode(idmap, inode,
+						    &new_mode, &acl);
+			if (ret)
+				goto out;
+		}
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode)) {
+			ret = acl ? -EINVAL : 0;
+			goto out;
+		}
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (acl) {
+		value = posix_acl_to_xattr(&init_user_ns, acl, &size, GFP_NOFS);
+		if (!value) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	if (new_mode != old_mode) {
+		newattrs.ia_ctime = current_time(inode);
+		newattrs.ia_mode = new_mode;
+		newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+		ret = __ceph_setattr(idmap, inode, &newattrs, NULL);
+		if (ret)
+			goto out_free;
+	}
+
+	ret = __ceph_setxattr(inode, name, value, size, 0);
+	if (ret) {
+		if (new_mode != old_mode) {
+			newattrs.ia_ctime = old_ctime;
+			newattrs.ia_mode = old_mode;
+			newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+			__ceph_setattr(idmap, inode, &newattrs, NULL);
+		}
+		goto out_free;
+	}
+
+	ceph_set_cached_acl(inode, type, acl);
+
+out_free:
+	kfree(value);
+out:
+	return ret;
+}
+
+int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
+		       struct ceph_acl_sec_ctx *as_ctx)
+{
+	struct posix_acl *acl, *default_acl;
+	size_t val_size1 = 0, val_size2 = 0;
+	struct ceph_pagelist *pagelist = NULL;
+	void *tmp_buf1 = NULL, *tmp_buf2 = NULL;
+	int err;
+
+	err = posix_acl_create(dir, mode, &default_acl, &acl);
+	if (err)
+		return err;
+
+	if (acl) {
+		err = posix_acl_equiv_mode(acl, mode);
+		if (err < 0)
+			goto out_err;
+		if (err == 0) {
+			posix_acl_release(acl);
+			acl = NULL;
+		}
+	}
+
+	if (!default_acl && !acl)
+		return 0;
+
+	err = -ENOMEM;
+	pagelist = ceph_pagelist_alloc(GFP_KERNEL);
+	if (!pagelist)
+		goto out_err;
+
+	err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
+	if (err)
+		goto out_err;
+
+	ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
+
+	if (acl) {
+		size_t len = strlen(XATTR_NAME_POSIX_ACL_ACCESS);
+
+		err = -ENOMEM;
+		tmp_buf1 = posix_acl_to_xattr(&init_user_ns, acl,
+					      &val_size1, GFP_KERNEL);
+		if (!tmp_buf1)
+			goto out_err;
+		err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
+		if (err)
+			goto out_err;
+		ceph_pagelist_encode_string(pagelist, XATTR_NAME_POSIX_ACL_ACCESS,
+					    len);
+		ceph_pagelist_encode_32(pagelist, val_size1);
+		ceph_pagelist_append(pagelist, tmp_buf1, val_size1);
+	}
+	if (default_acl) {
+		size_t len = strlen(XATTR_NAME_POSIX_ACL_DEFAULT);
+
+		err = -ENOMEM;
+		tmp_buf2 = posix_acl_to_xattr(&init_user_ns, default_acl,
+					      &val_size2, GFP_KERNEL);
+		if (!tmp_buf2)
+			goto out_err;
+		err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
+		if (err)
+			goto out_err;
+		ceph_pagelist_encode_string(pagelist,
+					  XATTR_NAME_POSIX_ACL_DEFAULT, len);
+		ceph_pagelist_encode_32(pagelist, val_size2);
+		ceph_pagelist_append(pagelist, tmp_buf2, val_size2);
+	}
+
+	kfree(tmp_buf1);
+	kfree(tmp_buf2);
+
+	as_ctx->acl = acl;
+	as_ctx->default_acl = default_acl;
+	as_ctx->pagelist = pagelist;
+	return 0;
+
+out_err:
+	posix_acl_release(acl);
+	posix_acl_release(default_acl);
+	kfree(tmp_buf1);
+	kfree(tmp_buf2);
+	if (pagelist)
+		ceph_pagelist_release(pagelist);
+	return err;
+}
+
+void ceph_init_inode_acls(struct inode *inode, struct ceph_acl_sec_ctx *as_ctx)
+{
+	if (!inode)
+		return;
+	ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, as_ctx->acl);
+	ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, as_ctx->default_acl);
+}