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

From: Kirill Korotaev
Date: Fri Sep 30 2005 - 06:31:51 EST


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->owner anyhow,
so setting it later manually is inatomic.
- looks like almost all modules do not care whether
it's de->owner is set...

Signed-Off-By: Denis Lunev <den@xxxxx>
Signed-Off-By: Kirill Korotaev <dev@xxxxx>
--- ./fs/proc/inode.c.procino 2005-09-30 13:17:21.000000000 +0400
+++ ./fs/proc/inode.c 2005-09-30 13:17:55.000000000 +0400
@@ -205,10 +205,13 @@ struct inode *proc_get_inode(struct supe

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) {
@@ -220,20 +223,20 @@ struct inode *proc_get_inode(struct supe
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)