[PATCH] proc: fix of error path in proc_get_inode()

Kirill Korotaev · Linus Torvalds · commit e95436597156 · 2005-10-30T17:37:21.000-08:00
This patch fixes incorrect error path in proc_get_inode(), when module
can't be get due to being unloaded.  When try_module_get() fails, this
function puts de(!) and still returns inode with non-getted de.

There are still unresolved known bugs in proc yet to be fixed:
- proc_dir_entry tree is managed without any serialization
- create_proc_entry() doesn't setup de-&gt;owner anyhow,
   so setting it later manually is inatomic.
- looks like almost all modules do not care whether
   it's de-&gt;owner is set...

Signed-Off-By: Denis Lunev &lt;den@sw.ru&gt;
Signed-Off-By: Kirill Korotaev &lt;dev@sw.ru&gt;
Signed-off-by: Andrew Morton &lt;akpm@osdl.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@osdl.org&gt;
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
@@ -156,10 +156,13 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 
 	WARN_ON(de && de->deleted);
 
+	if (de != NULL && !try_module_get(de->owner))
+		goto out_mod;
+
 	inode = iget(sb, ino);
 	if (!inode)
-		goto out_fail;
-	
+		goto out_ino;
+
 	PROC_I(inode)->pde = de;
 	if (de) {
 		if (de->mode) {
@@ -171,20 +174,20 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 			inode->i_size = de->size;
 		if (de->nlink)
 			inode->i_nlink = de->nlink;
-		if (!try_module_get(de->owner))
-			goto out_fail;
 		if (de->proc_iops)
 			inode->i_op = de->proc_iops;
 		if (de->proc_fops)
 			inode->i_fop = de->proc_fops;
 	}
 
-out:
 	return inode;
 
-out_fail:
+out_ino:
+	if (de != NULL)
+		module_put(de->owner);
+out_mod:
 	de_put(de);
-	goto out;
+	return NULL;
 }			
 
 int proc_fill_super(struct super_block *s, void *data, int silent)
