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-rw-r--r--security/selinux/hooks.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a049b7216270..4de09f0227b4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -254,10 +254,21 @@ static void inode_free_security(struct inode *inode)
struct inode_security_struct *isec = inode->i_security;
struct superblock_security_struct *sbsec = inode->i_sb->s_security;
- spin_lock(&sbsec->isec_lock);
- if (!list_empty(&isec->list))
+ /*
+ * As not all inode security structures are in a list, we check for
+ * empty list outside of the lock to make sure that we won't waste
+ * time taking a lock doing nothing.
+ *
+ * The list_del_init() function can be safely called more than once.
+ * It should not be possible for this function to be called with
+ * concurrent list_add(), but for better safety against future changes
+ * in the code, we use list_empty_careful() here.
+ */
+ if (!list_empty_careful(&isec->list)) {
+ spin_lock(&sbsec->isec_lock);
list_del_init(&isec->list);
- spin_unlock(&sbsec->isec_lock);
+ spin_unlock(&sbsec->isec_lock);
+ }
/*
* The inode may still be referenced in a path walk and