TOMOYO: Use mutex_lock_interruptible.

Some of TOMOYO's functions may sleep after mutex_lock(). If OOM-killer selected
a process which is waiting at mutex_lock(), the to-be-killed process can't be
killed. Thus, replace mutex_lock() with mutex_lock_interruptible() so that the
to-be-killed process can immediately return from TOMOYO's functions.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 0687ada28e82..060bbf3870ce 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -176,7 +176,8 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
                 return -ENOMEM;
         if (!is_delete)
                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list, list) {
                 if (ptr->filename != saved_filename)
                         continue;
@@ -192,6 +193,7 @@ static int tomoyo_update_globally_readable_entry(const char *filename,
                 error = 0;
         }
         mutex_unlock(&tomoyo_policy_lock);
+ out:
         tomoyo_put_name(saved_filename);
         kfree(entry);
         return error;
@@ -323,7 +325,8 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
                 goto out;
         if (!is_delete)
                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
                 if (saved_pattern != ptr->pattern)
                         continue;
@@ -476,7 +479,8 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
                 return error;
         if (!is_delete)
                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                goto out;
         list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
                 if (ptr->pattern != saved_pattern)
                         continue;
@@ -492,6 +496,7 @@ static int tomoyo_update_no_rewrite_entry(const char *pattern,
                 error = 0;
         }
         mutex_unlock(&tomoyo_policy_lock);
+ out:
         tomoyo_put_name(saved_pattern);
         kfree(entry);
         return error;
@@ -822,7 +827,8 @@ static int tomoyo_update_path_acl(const u8 type, const char *filename,
                 return -ENOMEM;
         if (!is_delete)
                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                goto out;
         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
                 struct tomoyo_path_acl *acl =
                         container_of(ptr, struct tomoyo_path_acl, head);
@@ -867,6 +873,7 @@ static int tomoyo_update_path_acl(const u8 type, const char *filename,
                 error = 0;
         }
         mutex_unlock(&tomoyo_policy_lock);
+ out:
         kfree(entry);
         tomoyo_put_name(saved_filename);
         return error;
@@ -908,7 +915,8 @@ static int tomoyo_update_path2_acl(const u8 type, const char *filename1,
                 goto out;
         if (!is_delete)
                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                goto out;
         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
                 struct tomoyo_path2_acl *acl =
                         container_of(ptr, struct tomoyo_path2_acl, head);