From 99b76233803beab302123d243eea9e41149804f3 Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Wed, 25 Mar 2009 22:48:06 +0300
Subject: proc 2/2: remove struct proc_dir_entry::owner
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.
We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.
But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.
->read_proc/->write_proc were just fixed to not require ->owner for
protection.
rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.
Removing ->owner will also make PDE smaller.
So, let's nuke it.
Kudos to Jeff Layton for reminding about this, let's say, oversight.
http://bugzilla.kernel.org/show_bug.cgi?id=12454
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
drivers/net/bonding/bond_main.c | 35 ++---------------------------------
1 file changed, 2 insertions(+), 33 deletions(-)
(limited to 'drivers/net/bonding')
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 9c326a50a3e..99610f358c4 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3444,25 +3444,12 @@ static void bond_remove_proc_entry(struct bonding *bond)
*/
static void bond_create_proc_dir(void)
{
- int len = strlen(DRV_NAME);
-
- for (bond_proc_dir = init_net.proc_net->subdir; bond_proc_dir;
- bond_proc_dir = bond_proc_dir->next) {
- if ((bond_proc_dir->namelen == len) &&
- !memcmp(bond_proc_dir->name, DRV_NAME, len)) {
- break;
- }
- }
-
if (!bond_proc_dir) {
bond_proc_dir = proc_mkdir(DRV_NAME, init_net.proc_net);
- if (bond_proc_dir) {
- bond_proc_dir->owner = THIS_MODULE;
- } else {
+ if (!bond_proc_dir)
printk(KERN_WARNING DRV_NAME
": Warning: cannot create /proc/net/%s\n",
DRV_NAME);
- }
}
}
@@ -3471,25 +3458,7 @@ static void bond_create_proc_dir(void)
*/
static void bond_destroy_proc_dir(void)
{
- struct proc_dir_entry *de;
-
- if (!bond_proc_dir) {
- return;
- }
-
- /* verify that the /proc dir is empty */
- for (de = bond_proc_dir->subdir; de; de = de->next) {
- /* ignore . and .. */
- if (*(de->name) != '.') {
- break;
- }
- }
-
- if (de) {
- if (bond_proc_dir->owner == THIS_MODULE) {
- bond_proc_dir->owner = NULL;
- }
- } else {
+ if (bond_proc_dir) {
remove_proc_entry(DRV_NAME, init_net.proc_net);
bond_proc_dir = NULL;
}
--
cgit