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, 8 insertions, 5 deletions

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 3c86bbc33aeb..8f34036fd31c 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -874,13 +874,13 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_domain_info * const domain)
 static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
                                                                 int profile)
 {
-        static DEFINE_MUTEX(lock);
         struct tomoyo_profile *ptr = NULL;
         int i;
 
         if (profile >= TOMOYO_MAX_PROFILES)
                 return NULL;
-        mutex_lock(&lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                return NULL;
         ptr = tomoyo_profile_ptr[profile];
         if (ptr)
                 goto ok;
@@ -895,7 +895,7 @@ static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
         mb(); /* Avoid out-of-order execution. */
         tomoyo_profile_ptr[profile] = ptr;
  ok:
-        mutex_unlock(&lock);
+        mutex_unlock(&tomoyo_policy_lock);
         return ptr;
 }
 
@@ -1090,7 +1090,8 @@ static int tomoyo_update_manager_entry(const char *manager,
                 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_policy_manager_list, list) {
                 if (ptr->manager != saved_manager)
                         continue;
@@ -1107,6 +1108,7 @@ static int tomoyo_update_manager_entry(const char *manager,
                 error = 0;
         }
         mutex_unlock(&tomoyo_policy_lock);
+ out:
         tomoyo_put_name(saved_manager);
         kfree(entry);
         return error;
@@ -1287,7 +1289,8 @@ static int tomoyo_delete_domain(char *domainname)
 
         name.name = domainname;
         tomoyo_fill_path_info(&name);
-        mutex_lock(&tomoyo_policy_lock);
+        if (mutex_lock_interruptible(&tomoyo_policy_lock))
+                return 0;
         /* Is there an active domain? */
         list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
                 /* Never delete tomoyo_kernel_domain */