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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Sasha Levin <sashal@kernel.org>,
        John Garry <john.garry@huawei.com>
Subject: [PATCH 5.4 189/203] tomoyo: Suppress RCU warning at list_for_each_entry_rcu().
Date:   Fri, 17 Jan 2020 00:18:26 +0100
Message-Id: <20200116231800.796145213@linuxfoundation.org>
In-Reply-To: <20200116231745.218684830@linuxfoundation.org>
References: <20200116231745.218684830@linuxfoundation.org>
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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

[ Upstream commit 6bd5ce6089b561f5392460bfb654dea89356ab1b ]

John Garry has reported that allmodconfig kernel on arm64 causes flood of
"RCU-list traversed in non-reader section!!" warning. I don't know what
change caused this warning, but this warning is safe because TOMOYO uses
SRCU lock instead. Let's suppress this warning by explicitly telling that
the caller is holding SRCU lock.

Reported-and-tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/tomoyo/common.c |  9 ++++++---
 security/tomoyo/domain.c | 15 ++++++++++-----
 security/tomoyo/group.c  |  9 ++++++---
 security/tomoyo/util.c   |  6 ++++--
 4 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index dd3d5942e669..c36bafbcd77e 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -951,7 +951,8 @@ static bool tomoyo_manager(void)
 	exe = tomoyo_get_exe();
 	if (!exe)
 		return false;
-	list_for_each_entry_rcu(ptr, &tomoyo_kernel_namespace.policy_list[TOMOYO_ID_MANAGER], head.list) {
+	list_for_each_entry_rcu(ptr, &tomoyo_kernel_namespace.policy_list[TOMOYO_ID_MANAGER], head.list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (!ptr->head.is_deleted &&
 		    (!tomoyo_pathcmp(domainname, ptr->manager) ||
 		     !strcmp(exe, ptr->manager->name))) {
@@ -1095,7 +1096,8 @@ static int tomoyo_delete_domain(char *domainname)
 	if (mutex_lock_interruptible(&tomoyo_policy_lock))
 		return -EINTR;
 	/* Is there an active domain? */
-	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		/* Never delete tomoyo_kernel_domain */
 		if (domain == &tomoyo_kernel_domain)
 			continue;
@@ -2778,7 +2780,8 @@ void tomoyo_check_profile(void)
 
 	tomoyo_policy_loaded = true;
 	pr_info("TOMOYO: 2.6.0\n");
-	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		const u8 profile = domain->profile;
 		struct tomoyo_policy_namespace *ns = domain->ns;
 
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 8526a0a74023..7869d6a9980b 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -41,7 +41,8 @@ int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
 
 	if (mutex_lock_interruptible(&tomoyo_policy_lock))
 		return -ENOMEM;
-	list_for_each_entry_rcu(entry, list, list) {
+	list_for_each_entry_rcu(entry, list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
 			continue;
 		if (!check_duplicate(entry, new_entry))
@@ -119,7 +120,8 @@ int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
 	}
 	if (mutex_lock_interruptible(&tomoyo_policy_lock))
 		goto out;
-	list_for_each_entry_rcu(entry, list, list) {
+	list_for_each_entry_rcu(entry, list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
 			continue;
 		if (!tomoyo_same_acl_head(entry, new_entry) ||
@@ -166,7 +168,8 @@ void tomoyo_check_acl(struct tomoyo_request_info *r,
 	u16 i = 0;
 
 retry:
-	list_for_each_entry_rcu(ptr, list, list) {
+	list_for_each_entry_rcu(ptr, list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (ptr->is_deleted || ptr->type != r->param_type)
 			continue;
 		if (!check_entry(r, ptr))
@@ -298,7 +301,8 @@ static inline bool tomoyo_scan_transition
 {
 	const struct tomoyo_transition_control *ptr;
 
-	list_for_each_entry_rcu(ptr, list, head.list) {
+	list_for_each_entry_rcu(ptr, list, head.list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (ptr->head.is_deleted || ptr->type != type)
 			continue;
 		if (ptr->domainname) {
@@ -735,7 +739,8 @@ retry:
 
 		/* Check 'aggregator' directive. */
 		candidate = &exename;
-		list_for_each_entry_rcu(ptr, list, head.list) {
+		list_for_each_entry_rcu(ptr, list, head.list,
+					srcu_read_lock_held(&tomoyo_ss)) {
 			if (ptr->head.is_deleted ||
 			    !tomoyo_path_matches_pattern(&exename,
 							 ptr->original_name))
diff --git a/security/tomoyo/group.c b/security/tomoyo/group.c
index a37c7dc66e44..1cecdd797597 100644
--- a/security/tomoyo/group.c
+++ b/security/tomoyo/group.c
@@ -133,7 +133,8 @@ tomoyo_path_matches_group(const struct tomoyo_path_info *pathname,
 {
 	struct tomoyo_path_group *member;
 
-	list_for_each_entry_rcu(member, &group->member_list, head.list) {
+	list_for_each_entry_rcu(member, &group->member_list, head.list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (member->head.is_deleted)
 			continue;
 		if (!tomoyo_path_matches_pattern(pathname, member->member_name))
@@ -161,7 +162,8 @@ bool tomoyo_number_matches_group(const unsigned long min,
 	struct tomoyo_number_group *member;
 	bool matched = false;
 
-	list_for_each_entry_rcu(member, &group->member_list, head.list) {
+	list_for_each_entry_rcu(member, &group->member_list, head.list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (member->head.is_deleted)
 			continue;
 		if (min > member->number.values[1] ||
@@ -191,7 +193,8 @@ bool tomoyo_address_matches_group(const bool is_ipv6, const __be32 *address,
 	bool matched = false;
 	const u8 size = is_ipv6 ? 16 : 4;
 
-	list_for_each_entry_rcu(member, &group->member_list, head.list) {
+	list_for_each_entry_rcu(member, &group->member_list, head.list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (member->head.is_deleted)
 			continue;
 		if (member->address.is_ipv6 != is_ipv6)
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index 52752e1a84ed..eba0b3395851 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -594,7 +594,8 @@ struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname)
 
 	name.name = domainname;
 	tomoyo_fill_path_info(&name);
-	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
+	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		if (!domain->is_deleted &&
 		    !tomoyo_pathcmp(&name, domain->domainname))
 			return domain;
@@ -1028,7 +1029,8 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r)
 		return false;
 	if (!domain)
 		return true;
-	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list,
+				srcu_read_lock_held(&tomoyo_ss)) {
 		u16 perm;
 		u8 i;
 
-- 
2.20.1