proc: detect duplicate names on registration

Print a warning if PDE is registered with a name which already exists in
target directory.

Bug report and a simple fix can be found here:
http://bugzilla.kernel.org/show_bug.cgi?id=8798

[\n fixlet and no undescriptive variable usage --adobriyan]
[akpm@linux-foundation.org: make printk comprehensible]
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index e37ea3e53de8..b9dd3628d43a 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -521,6 +521,7 @@ static const struct inode_operations proc_dir_inode_operations = {
 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
 {
         unsigned int i;
+        struct proc_dir_entry *tmp;
         
         i = get_inode_number();
         if (i == 0)
@@ -544,6 +545,15 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
         }
 
         spin_lock(&proc_subdir_lock);
+
+        for (tmp = dir->subdir; tmp; tmp = tmp->next)
+                if (strcmp(tmp->name, dp->name) == 0) {
+                        printk(KERN_WARNING "proc_dir_entry '%s' already "
+                                        "registered\n", dp->name);
+                        dump_stack();
+                        break;
+                }
+
         dp->next = dir->subdir;
         dp->parent = dir;
         dir->subdir = dp;