Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  nd->inode is not set on the second attempt in path_walk()
  unfuck proc_sysctl ->d_compare()
  minimal fix for do_filp_open() race

3 files changed, 22 insertions, 7 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 0087cf9c2c6b..a4689eb2df28 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1546,6 +1546,7 @@ static int path_walk(const char *name, struct nameidata *nd)
                 /* nd->path had been dropped */
                 current->total_link_count = 0;
                 nd->path = save;
+                nd->inode = save.dentry->d_inode;
                 path_get(&nd->path);
                 nd->flags |= LOOKUP_REVAL;
                 result = link_path_walk(name, nd);
@@ -2455,22 +2456,29 @@ struct file *do_filp_open(int dfd, const char *pathname,
         /* !O_CREAT, simple open */
         error = do_path_lookup(dfd, pathname, flags, &nd);
         if (unlikely(error))
-                goto out_filp;
+                goto out_filp2;
         error = -ELOOP;
         if (!(nd.flags & LOOKUP_FOLLOW)) {
                 if (nd.inode->i_op->follow_link)
-                        goto out_path;
+                        goto out_path2;
         }
         error = -ENOTDIR;
         if (nd.flags & LOOKUP_DIRECTORY) {
                 if (!nd.inode->i_op->lookup)
-                        goto out_path;
+                        goto out_path2;
         }
         audit_inode(pathname, nd.path.dentry);
         filp = finish_open(&nd, open_flag, acc_mode);
+out2:
         release_open_intent(&nd);
         return filp;
 
+out_path2:
+        path_put(&nd.path);
+out_filp2:
+        filp = ERR_PTR(error);
+        goto out2;
+
 creat:
         /* OK, have to create the file. Find the parent. */
         error = path_init_rcu(dfd, pathname,
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 176ce4cda68a..d6a7ca1fdac5 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -27,6 +27,7 @@
 static void proc_evict_inode(struct inode *inode)
 {
         struct proc_dir_entry *de;
+        struct ctl_table_header *head;
 
         truncate_inode_pages(&inode->i_data, 0);
         end_writeback(inode);
@@ -38,8 +39,11 @@ static void proc_evict_inode(struct inode *inode)
         de = PROC_I(inode)->pde;
         if (de)
                 pde_put(de);
-        if (PROC_I(inode)->sysctl)
-                sysctl_head_put(PROC_I(inode)->sysctl);
+        head = PROC_I(inode)->sysctl;
+        if (head) {
+                rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
+                sysctl_head_put(head);
+        }
 }
 
 struct vfsmount *proc_mnt;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 09a1f92a34ef..8eb2522111c5 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -408,15 +408,18 @@ static int proc_sys_compare(const struct dentry *parent,
                 const struct dentry *dentry, const struct inode *inode,
                 unsigned int len, const char *str, const struct qstr *name)
 {
+        struct ctl_table_header *head;
         /* Although proc doesn't have negative dentries, rcu-walk means
          * that inode here can be NULL */
+        /* AV: can it, indeed? */
         if (!inode)
-                return 0;
+                return 1;
         if (name->len != len)
                 return 1;
         if (memcmp(name->name, str, len))
                 return 1;
-        return !sysctl_is_seen(PROC_I(inode)->sysctl);
+        head = rcu_dereference(PROC_I(inode)->sysctl);
+        return !head || !sysctl_is_seen(head);
 }
 
 static const struct dentry_operations proc_sys_dentry_operations = {