4 files changed, 29 insertions, 9 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index 2524629..f9b5842 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -842,6 +842,12 @@ config TMPFS
 config HUGETLBFS
 	bool "HugeTLB file system support"
 	depends X86 || IA64 || PPC64 || SPARC64 || SUPERH || BROKEN
+	help
+	  hugetlbfs is a filesystem backing for HugeTLB pages, based on
+	  ramfs. For architectures that support it, say Y here and read
+	  <file:Documentation/vm/hugetlbpage.txt> for details.
+
+	  If unsure, say N.
 
 config HUGETLB_PAGE
 	def_bool HUGETLBFS
diff --git a/fs/exec.c b/fs/exec.c
index 4121bb5..3a79d97 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -712,7 +712,7 @@ static int de_thread(struct task_struct *tsk)
 		attach_pid(current, PIDTYPE_PID,  current->pid);
 		attach_pid(current, PIDTYPE_PGID, current->signal->pgrp);
 		attach_pid(current, PIDTYPE_SID,  current->signal->session);
-		list_add_tail(&current->tasks, &init_task.tasks);
+		list_add_tail_rcu(&current->tasks, &init_task.tasks);
 
 		current->group_leader = current;
 		leader->group_leader = current;
diff --git a/fs/locks.c b/fs/locks.c
index dda83d6..efad7988 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2230,7 +2230,12 @@ void steal_locks(fl_owner_t from)
 
 	lock_kernel();
 	j = 0;
-	rcu_read_lock();
+
+	/*
+	 * We are not taking a ref to the file structures, so
+	 * we need to acquire ->file_lock.
+	 */
+	spin_lock(&files->file_lock);
 	fdt = files_fdtable(files);
 	for (;;) {
 		unsigned long set;
@@ -2248,7 +2253,7 @@ void steal_locks(fl_owner_t from)
 			set >>= 1;
 		}
 	}
-	rcu_read_unlock();
+	spin_unlock(&files->file_lock);
 	unlock_kernel();
 }
 EXPORT_SYMBOL(steal_locks);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a3a3eec..6cc77dc 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -297,16 +297,20 @@ static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsm
 
 	files = get_files_struct(task);
 	if (files) {
-		rcu_read_lock();
+		/*
+		 * We are not taking a ref to the file structure, so we must
+		 * hold ->file_lock.
+		 */
+		spin_lock(&files->file_lock);
 		file = fcheck_files(files, fd);
 		if (file) {
 			*mnt = mntget(file->f_vfsmnt);
 			*dentry = dget(file->f_dentry);
-			rcu_read_unlock();
+			spin_unlock(&files->file_lock);
 			put_files_struct(files);
 			return 0;
 		}
-		rcu_read_unlock();
+		spin_unlock(&files->file_lock);
 		put_files_struct(files);
 	}
 	return -ENOENT;
@@ -1523,7 +1527,12 @@ static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry,
 	if (!files)
 		goto out_unlock;
 	inode->i_mode = S_IFLNK;
-	rcu_read_lock();
+
+	/*
+	 * We are not taking a ref to the file structure, so we must
+	 * hold ->file_lock.
+	 */
+	spin_lock(&files->file_lock);
 	file = fcheck_files(files, fd);
 	if (!file)
 		goto out_unlock2;
@@ -1531,7 +1540,7 @@ static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry,
 		inode->i_mode |= S_IRUSR | S_IXUSR;
 	if (file->f_mode & 2)
 		inode->i_mode |= S_IWUSR | S_IXUSR;
-	rcu_read_unlock();
+	spin_unlock(&files->file_lock);
 	put_files_struct(files);
 	inode->i_op = &proc_pid_link_inode_operations;
 	inode->i_size = 64;
@@ -1541,7 +1550,7 @@ static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry,
 	return NULL;
 
 out_unlock2:
-	rcu_read_unlock();
+	spin_unlock(&files->file_lock);
 	put_files_struct(files);
 out_unlock:
 	iput(inode);