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Date:	Fri, 4 Dec 2009 21:34:06 +0900
From:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To:	serue@...ibm.com
Cc:	linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] TOMOYO: Use RCU primitives for list operation

Hello.

Serge E. Hallyn wrote:
> If you'll be adding gc eventually anyway, is it really worthwhile
> to 'violate the rules' now by calling list_for_each_entry_rcu()
> without being inside rcu_read_lock() now?  I fear it'll only serve
> to confuse readers, especially those looking for rcu users to serve
> as examples.

You are right. I modified to call srcu_read_lock().

I don't modify tomoyo_file_permission() because it will be removed by
applying commit: c656ae95d1c5c8ed5763356263ace2d03087efec
(security/tomoyo: Remove now unnecessary handling of security_sysctl.).

Regards.
----------
[PATCH] TOMOYO: Use RCU primitives for list operation

Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().

Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
---
 security/tomoyo/common.c   |   90 ++++++++++++++++++++----------------
 security/tomoyo/common.h   |   28 ++++++++---
 security/tomoyo/domain.c   |   63 +++++++++++++++----------
 security/tomoyo/file.c     |  110 +++++++++++++++++++++++++++++++--------------
 security/tomoyo/realpath.c |    8 ++-
 security/tomoyo/tomoyo.c   |   20 ++++++--
 6 files changed, 207 insertions(+), 112 deletions(-)

--- security-testing-2.6.orig/security/tomoyo/common.c
+++ security-testing-2.6/security/tomoyo/common.c
@@ -365,10 +365,9 @@ bool tomoyo_is_domain_def(const unsigned
  *
  * @domainname: The domainname to find.
  *
- * Caller must call down_read(&tomoyo_domain_list_lock); or
- * down_write(&tomoyo_domain_list_lock); .
- *
  * Returns pointer to "struct tomoyo_domain_info" if found, NULL otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname)
 {
@@ -377,7 +376,7 @@ struct tomoyo_domain_info *tomoyo_find_d
 
 	name.name = domainname;
 	tomoyo_fill_path_info(&name);
-	list_for_each_entry(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 		if (!domain->is_deleted &&
 		    !tomoyo_pathcmp(&name, domain->domainname))
 			return domain;
@@ -829,6 +828,8 @@ bool tomoyo_verbose_mode(const struct to
  * @domain: Pointer to "struct tomoyo_domain_info".
  *
  * Returns true if the domain is not exceeded quota, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_domain_quota_is_ok(struct tomoyo_domain_info * const domain)
 {
@@ -837,8 +838,7 @@ bool tomoyo_domain_quota_is_ok(struct to
 
 	if (!domain)
 		return true;
-	down_read(&tomoyo_domain_acl_info_list_lock);
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (ptr->type & TOMOYO_ACL_DELETED)
 			continue;
 		switch (tomoyo_acl_type2(ptr)) {
@@ -891,7 +891,6 @@ bool tomoyo_domain_quota_is_ok(struct to
 			break;
 		}
 	}
-	up_read(&tomoyo_domain_acl_info_list_lock);
 	if (count < tomoyo_check_flags(domain, TOMOYO_MAX_ACCEPT_ENTRY))
 		return true;
 	if (!domain->quota_warned) {
@@ -1121,6 +1120,8 @@ static DECLARE_RWSEM(tomoyo_policy_manag
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_manager_entry(const char *manager,
 				       const bool is_delete)
@@ -1143,7 +1144,7 @@ static int tomoyo_update_manager_entry(c
 	if (!saved_manager)
 		return -ENOMEM;
 	down_write(&tomoyo_policy_manager_list_lock);
-	list_for_each_entry(ptr, &tomoyo_policy_manager_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
 		if (ptr->manager != saved_manager)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -1159,7 +1160,7 @@ static int tomoyo_update_manager_entry(c
 		goto out;
 	new_entry->manager = saved_manager;
 	new_entry->is_domain = is_domain;
-	list_add_tail(&new_entry->list, &tomoyo_policy_manager_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_policy_manager_list);
 	error = 0;
  out:
 	up_write(&tomoyo_policy_manager_list_lock);
@@ -1172,6 +1173,8 @@ static int tomoyo_update_manager_entry(c
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_write_manager_policy(struct tomoyo_io_buffer *head)
 {
@@ -1191,6 +1194,8 @@ static int tomoyo_write_manager_policy(s
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_read_manager_policy(struct tomoyo_io_buffer *head)
 {
@@ -1199,7 +1204,6 @@ static int tomoyo_read_manager_policy(st
 
 	if (head->read_eof)
 		return 0;
-	down_read(&tomoyo_policy_manager_list_lock);
 	list_for_each_cookie(pos, head->read_var2,
 			     &tomoyo_policy_manager_list) {
 		struct tomoyo_policy_manager_entry *ptr;
@@ -1211,7 +1215,6 @@ static int tomoyo_read_manager_policy(st
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_policy_manager_list_lock);
 	head->read_eof = done;
 	return 0;
 }
@@ -1221,6 +1224,8 @@ static int tomoyo_read_manager_policy(st
  *
  * Returns true if the current process is permitted to modify policy
  * via /sys/kernel/security/tomoyo/ interface.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_policy_manager(void)
 {
@@ -1234,29 +1239,25 @@ static bool tomoyo_is_policy_manager(voi
 		return true;
 	if (!tomoyo_manage_by_non_root && (task->cred->uid || task->cred->euid))
 		return false;
-	down_read(&tomoyo_policy_manager_list_lock);
-	list_for_each_entry(ptr, &tomoyo_policy_manager_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
 		if (!ptr->is_deleted && ptr->is_domain
 		    && !tomoyo_pathcmp(domainname, ptr->manager)) {
 			found = true;
 			break;
 		}
 	}
-	up_read(&tomoyo_policy_manager_list_lock);
 	if (found)
 		return true;
 	exe = tomoyo_get_exe();
 	if (!exe)
 		return false;
-	down_read(&tomoyo_policy_manager_list_lock);
-	list_for_each_entry(ptr, &tomoyo_policy_manager_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
 		if (!ptr->is_deleted && !ptr->is_domain
 		    && !strcmp(exe, ptr->manager->name)) {
 			found = true;
 			break;
 		}
 	}
-	up_read(&tomoyo_policy_manager_list_lock);
 	if (!found) { /* Reduce error messages. */
 		static pid_t last_pid;
 		const pid_t pid = current->pid;
@@ -1277,6 +1278,8 @@ static bool tomoyo_is_policy_manager(voi
  * @data: String to parse.
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_select_one(struct tomoyo_io_buffer *head,
 				 const char *data)
@@ -1292,11 +1295,8 @@ static bool tomoyo_is_select_one(struct 
 			domain = tomoyo_real_domain(p);
 		read_unlock(&tasklist_lock);
 	} else if (!strncmp(data, "domain=", 7)) {
-		if (tomoyo_is_domain_def(data + 7)) {
-			down_read(&tomoyo_domain_list_lock);
+		if (tomoyo_is_domain_def(data + 7))
 			domain = tomoyo_find_domain(data + 7);
-			up_read(&tomoyo_domain_list_lock);
-		}
 	} else
 		return false;
 	head->write_var1 = domain;
@@ -1310,13 +1310,11 @@ static bool tomoyo_is_select_one(struct 
 	if (domain) {
 		struct tomoyo_domain_info *d;
 		head->read_var1 = NULL;
-		down_read(&tomoyo_domain_list_lock);
-		list_for_each_entry(d, &tomoyo_domain_list, list) {
+		list_for_each_entry_rcu(d, &tomoyo_domain_list, list) {
 			if (d == domain)
 				break;
 			head->read_var1 = &d->list;
 		}
-		up_read(&tomoyo_domain_list_lock);
 		head->read_var2 = NULL;
 		head->read_bit = 0;
 		head->read_step = 0;
@@ -1332,6 +1330,8 @@ static bool tomoyo_is_select_one(struct 
  * @domainname: The name of domain.
  *
  * Returns 0.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_delete_domain(char *domainname)
 {
@@ -1342,7 +1342,7 @@ static int tomoyo_delete_domain(char *do
 	tomoyo_fill_path_info(&name);
 	down_write(&tomoyo_domain_list_lock);
 	/* Is there an active domain? */
-	list_for_each_entry(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 		/* Never delete tomoyo_kernel_domain */
 		if (domain == &tomoyo_kernel_domain)
 			continue;
@@ -1362,6 +1362,8 @@ static int tomoyo_delete_domain(char *do
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_write_domain_policy(struct tomoyo_io_buffer *head)
 {
@@ -1384,11 +1386,9 @@ static int tomoyo_write_domain_policy(st
 		domain = NULL;
 		if (is_delete)
 			tomoyo_delete_domain(data);
-		else if (is_select) {
-			down_read(&tomoyo_domain_list_lock);
+		else if (is_select)
 			domain = tomoyo_find_domain(data);
-			up_read(&tomoyo_domain_list_lock);
-		} else
+		else
 			domain = tomoyo_find_or_assign_new_domain(data, 0);
 		head->write_var1 = domain;
 		return 0;
@@ -1533,6 +1533,8 @@ static bool tomoyo_print_entry(struct to
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_read_domain_policy(struct tomoyo_io_buffer *head)
 {
@@ -1544,7 +1546,6 @@ static int tomoyo_read_domain_policy(str
 		return 0;
 	if (head->read_step == 0)
 		head->read_step = 1;
-	down_read(&tomoyo_domain_list_lock);
 	list_for_each_cookie(dpos, head->read_var1, &tomoyo_domain_list) {
 		struct tomoyo_domain_info *domain;
 		const char *quota_exceeded = "";
@@ -1577,7 +1578,6 @@ acl_loop:
 		if (head->read_step == 3)
 			goto tail_mark;
 		/* Print ACL entries in the domain. */
-		down_read(&tomoyo_domain_acl_info_list_lock);
 		list_for_each_cookie(apos, head->read_var2,
 				     &domain->acl_info_list) {
 			struct tomoyo_acl_info *ptr
@@ -1587,7 +1587,6 @@ acl_loop:
 			if (!done)
 				break;
 		}
-		up_read(&tomoyo_domain_acl_info_list_lock);
 		if (!done)
 			break;
 		head->read_step = 3;
@@ -1599,7 +1598,6 @@ tail_mark:
 		if (head->read_single_domain)
 			break;
 	}
-	up_read(&tomoyo_domain_list_lock);
 	head->read_eof = done;
 	return 0;
 }
@@ -1615,6 +1613,8 @@ tail_mark:
  *
  *     ( echo "select " $domainname; echo "use_profile " $profile ) |
  *     /usr/lib/ccs/loadpolicy -d
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_write_domain_profile(struct tomoyo_io_buffer *head)
 {
@@ -1626,9 +1626,7 @@ static int tomoyo_write_domain_profile(s
 	if (!cp)
 		return -EINVAL;
 	*cp = '\0';
-	down_read(&tomoyo_domain_list_lock);
 	domain = tomoyo_find_domain(cp + 1);
-	up_read(&tomoyo_domain_list_lock);
 	if (strict_strtoul(data, 10, &profile))
 		return -EINVAL;
 	if (domain && profile < TOMOYO_MAX_PROFILES
@@ -1650,6 +1648,8 @@ static int tomoyo_write_domain_profile(s
  *     awk ' { if ( domainname == "" ) { if ( $1 == "<kernel>" )
  *     domainname = $0; } else if ( $1 == "use_profile" ) {
  *     print $2 " " domainname; domainname = ""; } } ; '
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_read_domain_profile(struct tomoyo_io_buffer *head)
 {
@@ -1658,7 +1658,6 @@ static int tomoyo_read_domain_profile(st
 
 	if (head->read_eof)
 		return 0;
-	down_read(&tomoyo_domain_list_lock);
 	list_for_each_cookie(pos, head->read_var1, &tomoyo_domain_list) {
 		struct tomoyo_domain_info *domain;
 		domain = list_entry(pos, struct tomoyo_domain_info, list);
@@ -1669,7 +1668,6 @@ static int tomoyo_read_domain_profile(st
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_domain_list_lock);
 	head->read_eof = done;
 	return 0;
 }
@@ -1726,6 +1724,8 @@ static int tomoyo_read_pid(struct tomoyo
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_write_exception_policy(struct tomoyo_io_buffer *head)
 {
@@ -1760,6 +1760,8 @@ static int tomoyo_write_exception_policy
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns 0 on success, -EINVAL otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_read_exception_policy(struct tomoyo_io_buffer *head)
 {
@@ -1889,15 +1891,13 @@ void tomoyo_load_policy(const char *file
 	tomoyo_policy_loaded = true;
 	{ /* Check all profiles currently assigned to domains are defined. */
 		struct tomoyo_domain_info *domain;
-		down_read(&tomoyo_domain_list_lock);
-		list_for_each_entry(domain, &tomoyo_domain_list, list) {
+		list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 			const u8 profile = domain->profile;
 			if (tomoyo_profile_ptr[profile])
 				continue;
 			panic("Profile %u (used by '%s') not defined.\n",
 			      profile, domain->domainname->name);
 		}
-		up_read(&tomoyo_domain_list_lock);
 	}
 }
 
@@ -1945,6 +1945,8 @@ static int tomoyo_read_self_domain(struc
  * @file: Pointer to "struct file".
  *
  * Associates policy handler and returns 0 on success, -ENOMEM otherwise.
+ *
+ * Caller acquires tomoyo_read_lock().
  */
 static int tomoyo_open_control(const u8 type, struct file *file)
 {
@@ -2030,6 +2032,7 @@ static int tomoyo_open_control(const u8 
 			return -ENOMEM;
 		}
 	}
+	head->reader_idx = tomoyo_read_lock();
 	file->private_data = head;
 	/*
 	 * Call the handler now if the file is
@@ -2051,6 +2054,8 @@ static int tomoyo_open_control(const u8 
  * @buffer_len: Size of @buffer.
  *
  * Returns bytes read on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_read_control(struct file *file, char __user *buffer,
 			       const int buffer_len)
@@ -2094,6 +2099,8 @@ static int tomoyo_read_control(struct fi
  * @buffer_len: Size of @buffer.
  *
  * Returns @buffer_len on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_write_control(struct file *file, const char __user *buffer,
 				const int buffer_len)
@@ -2144,11 +2151,14 @@ static int tomoyo_write_control(struct f
  * @file: Pointer to "struct file".
  *
  * Releases memory and returns 0.
+ *
+ * Caller looses tomoyo_read_lock().
  */
 static int tomoyo_close_control(struct file *file)
 {
 	struct tomoyo_io_buffer *head = file->private_data;
 
+	tomoyo_read_unlock(head->reader_idx);
 	/* Release memory used for policy I/O. */
 	tomoyo_free(head->read_buf);
 	head->read_buf = NULL;
--- security-testing-2.6.orig/security/tomoyo/common.h
+++ security-testing-2.6/security/tomoyo/common.h
@@ -265,6 +265,8 @@ struct tomoyo_io_buffer {
 	int (*write) (struct tomoyo_io_buffer *);
 	/* Exclusive lock for this structure.   */
 	struct mutex io_sem;
+	/* Index returned by tomoyo_read_lock(). */
+	int reader_idx;
 	/* The position currently reading from. */
 	struct list_head *read_var1;
 	/* Extra variables for reading.         */
@@ -442,16 +444,28 @@ extern struct tomoyo_domain_info tomoyo_
  * @cookie:     the &struct list_head to use as a cookie.
  * @head:       the head for your list.
  *
- * Same with list_for_each() except that this primitive uses @cookie
+ * Same with list_for_each_rcu() except that this primitive uses @cookie
  * so that we can continue iteration.
  * @cookie must be NULL when iteration starts, and @cookie will become
  * NULL when iteration finishes.
  */
-#define list_for_each_cookie(pos, cookie, head)                       \
-	for (({ if (!cookie)                                          \
-				     cookie = head; }),               \
-	     pos = (cookie)->next;                                    \
-	     prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
-	     (cookie) = pos, pos = pos->next)
+#define list_for_each_cookie(pos, cookie, head)				\
+	for (({ if (!cookie)						\
+				     cookie = head; }),			\
+		     pos = rcu_dereference((cookie)->next);		\
+	     prefetch(pos->next), pos != (head) || ((cookie) = NULL);	\
+	     (cookie) = pos, pos = rcu_dereference(pos->next))
+
+extern struct srcu_struct tomoyo_ss;
+
+static inline int tomoyo_read_lock(void)
+{
+	return srcu_read_lock(&tomoyo_ss);
+}
+
+static inline void tomoyo_read_unlock(int idx)
+{
+	srcu_read_unlock(&tomoyo_ss, idx);
+}
 
 #endif /* !defined(_SECURITY_TOMOYO_COMMON_H) */
--- security-testing-2.6.orig/security/tomoyo/domain.c
+++ security-testing-2.6/security/tomoyo/domain.c
@@ -217,6 +217,8 @@ static DECLARE_RWSEM(tomoyo_domain_initi
  * @is_delete:  True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_domain_initializer_entry(const char *domainname,
 						  const char *program,
@@ -246,7 +248,7 @@ static int tomoyo_update_domain_initiali
 	if (!saved_program)
 		return -ENOMEM;
 	down_write(&tomoyo_domain_initializer_list_lock);
-	list_for_each_entry(ptr, &tomoyo_domain_initializer_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 		if (ptr->is_not != is_not ||
 		    ptr->domainname != saved_domainname ||
 		    ptr->program != saved_program)
@@ -266,7 +268,7 @@ static int tomoyo_update_domain_initiali
 	new_entry->program = saved_program;
 	new_entry->is_not = is_not;
 	new_entry->is_last_name = is_last_name;
-	list_add_tail(&new_entry->list, &tomoyo_domain_initializer_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_domain_initializer_list);
 	error = 0;
  out:
 	up_write(&tomoyo_domain_initializer_list_lock);
@@ -279,13 +281,14 @@ static int tomoyo_update_domain_initiali
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_domain_initializer_list_lock);
 	list_for_each_cookie(pos, head->read_var2,
 			     &tomoyo_domain_initializer_list) {
 		const char *no;
@@ -308,7 +311,6 @@ bool tomoyo_read_domain_initializer_poli
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_domain_initializer_list_lock);
 	return done;
 }
 
@@ -320,6 +322,8 @@ bool tomoyo_read_domain_initializer_poli
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
 					   const bool is_delete)
@@ -345,6 +349,8 @@ int tomoyo_write_domain_initializer_poli
  *
  * Returns true if executing @program reinitializes domain transition,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
 					 domainname,
@@ -355,8 +361,7 @@ static bool tomoyo_is_domain_initializer
 	struct tomoyo_domain_initializer_entry *ptr;
 	bool flag = false;
 
-	down_read(&tomoyo_domain_initializer_list_lock);
-	list_for_each_entry(ptr,  &tomoyo_domain_initializer_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (ptr->domainname) {
@@ -376,7 +381,6 @@ static bool tomoyo_is_domain_initializer
 		}
 		flag = true;
 	}
-	up_read(&tomoyo_domain_initializer_list_lock);
 	return flag;
 }
 
@@ -430,6 +434,8 @@ static DECLARE_RWSEM(tomoyo_domain_keepe
  * @is_delete:  True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_domain_keeper_entry(const char *domainname,
 					     const char *program,
@@ -459,7 +465,7 @@ static int tomoyo_update_domain_keeper_e
 	if (!saved_domainname)
 		return -ENOMEM;
 	down_write(&tomoyo_domain_keeper_list_lock);
-	list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 		if (ptr->is_not != is_not ||
 		    ptr->domainname != saved_domainname ||
 		    ptr->program != saved_program)
@@ -479,7 +485,7 @@ static int tomoyo_update_domain_keeper_e
 	new_entry->program = saved_program;
 	new_entry->is_not = is_not;
 	new_entry->is_last_name = is_last_name;
-	list_add_tail(&new_entry->list, &tomoyo_domain_keeper_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_domain_keeper_list);
 	error = 0;
  out:
 	up_write(&tomoyo_domain_keeper_list_lock);
@@ -493,6 +499,7 @@ static int tomoyo_update_domain_keeper_e
  * @is_not:    True if it is "no_keep_domain" entry.
  * @is_delete: True if it is a delete request.
  *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 				      const bool is_delete)
@@ -513,13 +520,14 @@ int tomoyo_write_domain_keeper_policy(ch
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_domain_keeper_list_lock);
 	list_for_each_cookie(pos, head->read_var2,
 			     &tomoyo_domain_keeper_list) {
 		struct tomoyo_domain_keeper_entry *ptr;
@@ -542,7 +550,6 @@ bool tomoyo_read_domain_keeper_policy(st
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_domain_keeper_list_lock);
 	return done;
 }
 
@@ -555,6 +562,8 @@ bool tomoyo_read_domain_keeper_policy(st
  *
  * Returns true if executing @program supresses domain transition,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 				    const struct tomoyo_path_info *program,
@@ -563,8 +572,7 @@ static bool tomoyo_is_domain_keeper(cons
 	struct tomoyo_domain_keeper_entry *ptr;
 	bool flag = false;
 
-	down_read(&tomoyo_domain_keeper_list_lock);
-	list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (!ptr->is_last_name) {
@@ -582,7 +590,6 @@ static bool tomoyo_is_domain_keeper(cons
 		}
 		flag = true;
 	}
-	up_read(&tomoyo_domain_keeper_list_lock);
 	return flag;
 }
 
@@ -627,6 +634,8 @@ static DECLARE_RWSEM(tomoyo_alias_list_l
  * @is_delete:     True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_alias_entry(const char *original_name,
 				     const char *aliased_name,
@@ -646,7 +655,7 @@ static int tomoyo_update_alias_entry(con
 	if (!saved_original_name || !saved_aliased_name)
 		return -ENOMEM;
 	down_write(&tomoyo_alias_list_lock);
-	list_for_each_entry(ptr, &tomoyo_alias_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 		if (ptr->original_name != saved_original_name ||
 		    ptr->aliased_name != saved_aliased_name)
 			continue;
@@ -663,7 +672,7 @@ static int tomoyo_update_alias_entry(con
 		goto out;
 	new_entry->original_name = saved_original_name;
 	new_entry->aliased_name = saved_aliased_name;
-	list_add_tail(&new_entry->list, &tomoyo_alias_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_alias_list);
 	error = 0;
  out:
 	up_write(&tomoyo_alias_list_lock);
@@ -676,13 +685,14 @@ static int tomoyo_update_alias_entry(con
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_alias_list_lock);
 	list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
 		struct tomoyo_alias_entry *ptr;
 
@@ -695,7 +705,6 @@ bool tomoyo_read_alias_policy(struct tom
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_alias_list_lock);
 	return done;
 }
 
@@ -706,6 +715,8 @@ bool tomoyo_read_alias_policy(struct tom
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 {
@@ -724,6 +735,8 @@ int tomoyo_write_alias_policy(char *data
  * @profile:    Profile number to assign if the domain was newly created.
  *
  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 							    domainname,
@@ -742,7 +755,7 @@ struct tomoyo_domain_info *tomoyo_find_o
 	if (!saved_domainname)
 		goto out;
 	/* Can I reuse memory of deleted domain? */
-	list_for_each_entry(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 		struct task_struct *p;
 		struct tomoyo_acl_info *ptr;
 		bool flag;
@@ -760,7 +773,7 @@ struct tomoyo_domain_info *tomoyo_find_o
 		read_unlock(&tasklist_lock);
 		if (flag)
 			continue;
-		list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 			ptr->type |= TOMOYO_ACL_DELETED;
 		}
 		tomoyo_set_domain_flag(domain, true, domain->flags);
@@ -776,7 +789,7 @@ struct tomoyo_domain_info *tomoyo_find_o
 		INIT_LIST_HEAD(&domain->acl_info_list);
 		domain->domainname = saved_domainname;
 		domain->profile = profile;
-		list_add_tail(&domain->list, &tomoyo_domain_list);
+		list_add_tail_rcu(&domain->list, &tomoyo_domain_list);
 	}
  out:
 	up_write(&tomoyo_domain_list_lock);
@@ -789,6 +802,8 @@ struct tomoyo_domain_info *tomoyo_find_o
  * @bprm: Pointer to "struct linux_binprm".
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 {
@@ -849,8 +864,7 @@ int tomoyo_find_next_domain(struct linux
 	if (tomoyo_pathcmp(&r, &s)) {
 		struct tomoyo_alias_entry *ptr;
 		/* Is this program allowed to be called via symbolic links? */
-		down_read(&tomoyo_alias_list_lock);
-		list_for_each_entry(ptr, &tomoyo_alias_list, list) {
+		list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 			if (ptr->is_deleted ||
 			    tomoyo_pathcmp(&r, ptr->original_name) ||
 			    tomoyo_pathcmp(&s, ptr->aliased_name))
@@ -861,7 +875,6 @@ int tomoyo_find_next_domain(struct linux
 			tomoyo_fill_path_info(&r);
 			break;
 		}
-		up_read(&tomoyo_alias_list_lock);
 	}
 
 	/* Check execute permission. */
@@ -892,9 +905,7 @@ int tomoyo_find_next_domain(struct linux
 	}
 	if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
 		goto done;
-	down_read(&tomoyo_domain_list_lock);
 	domain = tomoyo_find_domain(new_domain_name);
-	up_read(&tomoyo_domain_list_lock);
 	if (domain)
 		goto done;
 	if (is_enforce)
--- security-testing-2.6.orig/security/tomoyo/file.c
+++ security-testing-2.6/security/tomoyo/file.c
@@ -205,6 +205,8 @@ static DECLARE_RWSEM(tomoyo_globally_rea
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_globally_readable_entry(const char *filename,
 						 const bool is_delete)
@@ -220,7 +222,7 @@ static int tomoyo_update_globally_readab
 	if (!saved_filename)
 		return -ENOMEM;
 	down_write(&tomoyo_globally_readable_list_lock);
-	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
 		if (ptr->filename != saved_filename)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -235,7 +237,7 @@ static int tomoyo_update_globally_readab
 	if (!new_entry)
 		goto out;
 	new_entry->filename = saved_filename;
-	list_add_tail(&new_entry->list, &tomoyo_globally_readable_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_globally_readable_list);
 	error = 0;
  out:
 	up_write(&tomoyo_globally_readable_list_lock);
@@ -248,21 +250,22 @@ static int tomoyo_update_globally_readab
  * @filename: The filename to check.
  *
  * Returns true if any domain can open @filename for reading, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_globally_readable_file(const struct tomoyo_path_info *
 					     filename)
 {
 	struct tomoyo_globally_readable_file_entry *ptr;
 	bool found = false;
-	down_read(&tomoyo_globally_readable_list_lock);
-	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+
+	list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
 		if (!ptr->is_deleted &&
 		    tomoyo_path_matches_pattern(filename, ptr->filename)) {
 			found = true;
 			break;
 		}
 	}
-	up_read(&tomoyo_globally_readable_list_lock);
 	return found;
 }
 
@@ -273,6 +276,8 @@ static bool tomoyo_is_globally_readable_
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_globally_readable_policy(char *data, const bool is_delete)
 {
@@ -285,13 +290,14 @@ int tomoyo_write_globally_readable_polic
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_globally_readable_list_lock);
 	list_for_each_cookie(pos, head->read_var2,
 			     &tomoyo_globally_readable_list) {
 		struct tomoyo_globally_readable_file_entry *ptr;
@@ -305,7 +311,6 @@ bool tomoyo_read_globally_readable_polic
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_globally_readable_list_lock);
 	return done;
 }
 
@@ -348,6 +353,8 @@ static DECLARE_RWSEM(tomoyo_pattern_list
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_file_pattern_entry(const char *pattern,
 					    const bool is_delete)
@@ -363,7 +370,7 @@ static int tomoyo_update_file_pattern_en
 	if (!saved_pattern)
 		return -ENOMEM;
 	down_write(&tomoyo_pattern_list_lock);
-	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
 		if (saved_pattern != ptr->pattern)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -378,7 +385,7 @@ static int tomoyo_update_file_pattern_en
 	if (!new_entry)
 		goto out;
 	new_entry->pattern = saved_pattern;
-	list_add_tail(&new_entry->list, &tomoyo_pattern_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_pattern_list);
 	error = 0;
  out:
 	up_write(&tomoyo_pattern_list_lock);
@@ -391,6 +398,8 @@ static int tomoyo_update_file_pattern_en
  * @filename: The filename to find patterned pathname.
  *
  * Returns pointer to pathname pattern if matched, @filename otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static const struct tomoyo_path_info *
 tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
@@ -398,8 +407,7 @@ tomoyo_get_file_pattern(const struct tom
 	struct tomoyo_pattern_entry *ptr;
 	const struct tomoyo_path_info *pattern = NULL;
 
-	down_read(&tomoyo_pattern_list_lock);
-	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
@@ -412,7 +420,6 @@ tomoyo_get_file_pattern(const struct tom
 			break;
 		}
 	}
-	up_read(&tomoyo_pattern_list_lock);
 	if (pattern)
 		filename = pattern;
 	return filename;
@@ -425,6 +432,8 @@ tomoyo_get_file_pattern(const struct tom
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_pattern_policy(char *data, const bool is_delete)
 {
@@ -437,13 +446,14 @@ int tomoyo_write_pattern_policy(char *da
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_pattern_list_lock);
 	list_for_each_cookie(pos, head->read_var2, &tomoyo_pattern_list) {
 		struct tomoyo_pattern_entry *ptr;
 		ptr = list_entry(pos, struct tomoyo_pattern_entry, list);
@@ -454,7 +464,6 @@ bool tomoyo_read_file_pattern(struct tom
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_pattern_list_lock);
 	return done;
 }
 
@@ -497,6 +506,8 @@ static DECLARE_RWSEM(tomoyo_no_rewrite_l
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_no_rewrite_entry(const char *pattern,
 					  const bool is_delete)
@@ -511,7 +522,7 @@ static int tomoyo_update_no_rewrite_entr
 	if (!saved_pattern)
 		return -ENOMEM;
 	down_write(&tomoyo_no_rewrite_list_lock);
-	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
 		if (ptr->pattern != saved_pattern)
 			continue;
 		ptr->is_deleted = is_delete;
@@ -526,7 +537,7 @@ static int tomoyo_update_no_rewrite_entr
 	if (!new_entry)
 		goto out;
 	new_entry->pattern = saved_pattern;
-	list_add_tail(&new_entry->list, &tomoyo_no_rewrite_list);
+	list_add_tail_rcu(&new_entry->list, &tomoyo_no_rewrite_list);
 	error = 0;
  out:
 	up_write(&tomoyo_no_rewrite_list_lock);
@@ -540,14 +551,15 @@ static int tomoyo_update_no_rewrite_entr
  *
  * Returns true if @filename is specified by "deny_rewrite" directive,
  * false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static bool tomoyo_is_no_rewrite_file(const struct tomoyo_path_info *filename)
 {
 	struct tomoyo_no_rewrite_entry *ptr;
 	bool found = false;
 
-	down_read(&tomoyo_no_rewrite_list_lock);
-	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
 		if (ptr->is_deleted)
 			continue;
 		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
@@ -555,7 +567,6 @@ static bool tomoyo_is_no_rewrite_file(co
 		found = true;
 		break;
 	}
-	up_read(&tomoyo_no_rewrite_list_lock);
 	return found;
 }
 
@@ -566,6 +577,8 @@ static bool tomoyo_is_no_rewrite_file(co
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete)
 {
@@ -578,13 +591,14 @@ int tomoyo_write_no_rewrite_policy(char 
  * @head: Pointer to "struct tomoyo_io_buffer".
  *
  * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head)
 {
 	struct list_head *pos;
 	bool done = true;
 
-	down_read(&tomoyo_no_rewrite_list_lock);
 	list_for_each_cookie(pos, head->read_var2, &tomoyo_no_rewrite_list) {
 		struct tomoyo_no_rewrite_entry *ptr;
 		ptr = list_entry(pos, struct tomoyo_no_rewrite_entry, list);
@@ -595,7 +609,6 @@ bool tomoyo_read_no_rewrite_policy(struc
 		if (!done)
 			break;
 	}
-	up_read(&tomoyo_no_rewrite_list_lock);
 	return done;
 }
 
@@ -613,6 +626,8 @@ bool tomoyo_read_no_rewrite_policy(struc
  * Current policy syntax uses "allow_read/write" instead of "6",
  * "allow_read" instead of "4", "allow_write" instead of "2",
  * "allow_execute" instead of "1".
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_file_acl(const char *filename, u8 perm,
 				  struct tomoyo_domain_info * const domain,
@@ -650,6 +665,8 @@ static int tomoyo_update_file_acl(const 
  * @may_use_pattern: True if patterned ACL is permitted.
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
 					 domain,
@@ -661,8 +678,7 @@ static int tomoyo_check_single_path_acl2
 	struct tomoyo_acl_info *ptr;
 	int error = -EPERM;
 
-	down_read(&tomoyo_domain_acl_info_list_lock);
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		struct tomoyo_single_path_acl_record *acl;
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
@@ -680,7 +696,6 @@ static int tomoyo_check_single_path_acl2
 		error = 0;
 		break;
 	}
-	up_read(&tomoyo_domain_acl_info_list_lock);
 	return error;
 }
 
@@ -692,6 +707,8 @@ static int tomoyo_check_single_path_acl2
  * @operation: Mode ("read" or "write" or "read/write" or "execute").
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_file_acl(const struct tomoyo_domain_info *domain,
 				 const struct tomoyo_path_info *filename,
@@ -725,6 +742,8 @@ static int tomoyo_check_file_acl(const s
  * @mode:      Access control mode.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_file_perm2(struct tomoyo_domain_info * const domain,
 				   const struct tomoyo_path_info *filename,
@@ -778,6 +797,8 @@ static int tomoyo_check_file_perm2(struc
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
 			     const bool is_delete)
@@ -825,6 +846,8 @@ int tomoyo_write_file_policy(char *data,
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
 					 struct tomoyo_domain_info *
@@ -848,7 +871,7 @@ static int tomoyo_update_single_path_acl
 	down_write(&tomoyo_domain_acl_info_list_lock);
 	if (is_delete)
 		goto delete;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
@@ -875,12 +898,12 @@ static int tomoyo_update_single_path_acl
 	if (perm == (1 << TOMOYO_TYPE_READ_WRITE_ACL))
 		acl->perm |= rw_mask;
 	acl->filename = saved_filename;
-	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	list_add_tail_rcu(&acl->head.list, &domain->acl_info_list);
 	error = 0;
 	goto out;
  delete:
 	error = -ENOENT;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
@@ -912,6 +935,8 @@ static int tomoyo_update_single_path_acl
  * @is_delete: True if it is a delete request.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
 					 const char *filename2,
@@ -937,7 +962,7 @@ static int tomoyo_update_double_path_acl
 	down_write(&tomoyo_domain_acl_info_list_lock);
 	if (is_delete)
 		goto delete;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
@@ -960,12 +985,12 @@ static int tomoyo_update_double_path_acl
 	acl->perm = perm;
 	acl->filename1 = saved_filename1;
 	acl->filename2 = saved_filename2;
-	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	list_add_tail_rcu(&acl->head.list, &domain->acl_info_list);
 	error = 0;
 	goto out;
  delete:
 	error = -ENOENT;
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
 		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
@@ -992,6 +1017,8 @@ static int tomoyo_update_double_path_acl
  * @filename: Filename to check.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_acl(struct tomoyo_domain_info *domain,
 					const u8 type,
@@ -1011,6 +1038,8 @@ static int tomoyo_check_single_path_acl(
  * @filename2: Second filename to check.
  *
  * Returns 0 on success, -EPERM otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
 					const u8 type,
@@ -1025,8 +1054,7 @@ static int tomoyo_check_double_path_acl(
 
 	if (!tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE))
 		return 0;
-	down_read(&tomoyo_domain_acl_info_list_lock);
-	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 		struct tomoyo_double_path_acl_record *acl;
 		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
 			continue;
@@ -1041,7 +1069,6 @@ static int tomoyo_check_double_path_acl(
 		error = 0;
 		break;
 	}
-	up_read(&tomoyo_domain_acl_info_list_lock);
 	return error;
 }
 
@@ -1054,6 +1081,8 @@ static int tomoyo_check_double_path_acl(
  * @mode:      Access control mode.
  *
  * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_check_single_path_permission2(struct tomoyo_domain_info *
 						const domain, u8 operation,
@@ -1123,6 +1152,8 @@ int tomoyo_check_file_perm(struct tomoyo
  * @filename: Check permission for "execute".
  *
  * Returns 0 on success, negativevalue otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
  */
 int tomoyo_check_exec_perm(struct tomoyo_domain_info *domain,
 			   const struct tomoyo_path_info *filename)
@@ -1151,6 +1182,7 @@ int tomoyo_check_open_permission(struct 
 	struct tomoyo_path_info *buf;
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
+	int idx;
 
 	if (!mode || !path->mnt)
 		return 0;
@@ -1162,6 +1194,7 @@ int tomoyo_check_open_permission(struct 
 		 * don't call me.
 		 */
 		return 0;
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(path);
 	if (!buf)
 		goto out;
@@ -1187,6 +1220,7 @@ int tomoyo_check_open_permission(struct 
 							     buf, mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1208,9 +1242,11 @@ int tomoyo_check_1path_perm(struct tomoy
 	struct tomoyo_path_info *buf;
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
+	int idx;
 
 	if (!mode || !path->mnt)
 		return 0;
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(path);
 	if (!buf)
 		goto out;
@@ -1229,6 +1265,7 @@ int tomoyo_check_1path_perm(struct tomoy
 						     mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1249,9 +1286,12 @@ int tomoyo_check_rewrite_permission(stru
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
 	struct tomoyo_path_info *buf;
+	int idx;
 
 	if (!mode || !filp->f_path.mnt)
 		return 0;
+
+	idx = tomoyo_read_lock();
 	buf = tomoyo_get_path(&filp->f_path);
 	if (!buf)
 		goto out;
@@ -1264,6 +1304,7 @@ int tomoyo_check_rewrite_permission(stru
 						     buf, mode);
  out:
 	tomoyo_free(buf);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
@@ -1288,9 +1329,11 @@ int tomoyo_check_2path_perm(struct tomoy
 	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == 3);
 	const char *msg;
+	int idx;
 
 	if (!mode || !path1->mnt || !path2->mnt)
 		return 0;
+	idx = tomoyo_read_lock();
 	buf1 = tomoyo_get_path(path1);
 	buf2 = tomoyo_get_path(path2);
 	if (!buf1 || !buf2)
@@ -1329,6 +1372,7 @@ int tomoyo_check_2path_perm(struct tomoy
  out:
 	tomoyo_free(buf1);
 	tomoyo_free(buf2);
+	tomoyo_read_unlock(idx);
 	if (!is_enforce)
 		error = 0;
 	return error;
--- security-testing-2.6.orig/security/tomoyo/realpath.c
+++ security-testing-2.6/security/tomoyo/realpath.c
@@ -392,11 +392,13 @@ void __init tomoyo_realpath_init(void)
 		INIT_LIST_HEAD(&tomoyo_name_list[i]);
 	INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
 	tomoyo_kernel_domain.domainname = tomoyo_save_name(TOMOYO_ROOT_NAME);
-	list_add_tail(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
-	down_read(&tomoyo_domain_list_lock);
+	/*
+	 * tomoyo_read_lock() is not needed because this function is
+	 * called before the first "delete" request.
+	 */
+	list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
 	if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
 		panic("Can't register tomoyo_kernel_domain");
-	up_read(&tomoyo_domain_list_lock);
 }
 
 /* Memory allocated for temporary purpose. */
--- security-testing-2.6.orig/security/tomoyo/tomoyo.c
+++ security-testing-2.6/security/tomoyo/tomoyo.c
@@ -76,8 +76,18 @@ static int tomoyo_bprm_check_security(st
 	 * Execute permission is checked against pathname passed to do_execve()
 	 * using current domain.
 	 */
-	if (!domain)
-		return tomoyo_find_next_domain(bprm);
+	if (!domain) {
+		/*
+		 * We will need to protect whole execve() operation when GC
+		 * starts kfree()ing "struct tomoyo_domain_info" because
+		 * bprm->cred->security points to "struct tomoyo_domain_info"
+		 * but "struct tomoyo_domain_info" does not have a refcounter.
+		 */
+		const int idx = tomoyo_read_lock();
+		const int err = tomoyo_find_next_domain(bprm);
+		tomoyo_read_unlock(idx);
+		return err;
+	}
 	/*
 	 * Read permission is checked against interpreters using next domain.
 	 * '1' is the result of open_to_namei_flags(O_RDONLY).
@@ -297,6 +307,9 @@ static struct security_operations tomoyo
 	.path_rename         = tomoyo_path_rename,
 };
 
+/* Lock for GC. */
+struct srcu_struct tomoyo_ss;
+
 static int __init tomoyo_init(void)
 {
 	struct cred *cred = (struct cred *) current_cred();
@@ -304,7 +317,8 @@ static int __init tomoyo_init(void)
 	if (!security_module_enable(&tomoyo_security_ops))
 		return 0;
 	/* register ourselves with the security framework */
-	if (register_security(&tomoyo_security_ops))
+	if (register_security(&tomoyo_security_ops) ||
+	    init_srcu_struct(&tomoyo_ss))
 		panic("Failure registering TOMOYO Linux");
 	printk(KERN_INFO "TOMOYO Linux initialized\n");
 	cred->security = &tomoyo_kernel_domain;
--
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