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authorAlexey Dobriyan <adobriyan@gmail.com>2009-03-25 20:48:06 +0100
committerAlexey Dobriyan <adobriyan@gmail.com>2009-03-30 23:14:44 +0200
commit99b76233803beab302123d243eea9e41149804f3 (patch)
tree398178210fe66845ccd6fa4258ba762a87e023ad /drivers/net
parentproc 1/2: do PDE usecounting even for ->read_proc, ->write_proc (diff)
downloadlinux-99b76233803beab302123d243eea9e41149804f3.tar.xz
linux-99b76233803beab302123d243eea9e41149804f3.zip
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>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/bonding/bond_main.c35
-rw-r--r--drivers/net/irda/vlsi_ir.c7
-rw-r--r--drivers/net/wireless/airo.c1
3 files changed, 2 insertions, 41 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 9c326a50a3ee..99610f358c40 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;
}
diff --git a/drivers/net/irda/vlsi_ir.c b/drivers/net/irda/vlsi_ir.c
index 1243bc8e0035..ac0e4b6b6b66 100644
--- a/drivers/net/irda/vlsi_ir.c
+++ b/drivers/net/irda/vlsi_ir.c
@@ -1871,13 +1871,6 @@ static int __init vlsi_mod_init(void)
* without procfs - it's not required for the driver to work.
*/
vlsi_proc_root = proc_mkdir(PROC_DIR, NULL);
- if (vlsi_proc_root) {
- /* protect registered procdir against module removal.
- * Because we are in the module init path there's no race
- * window after create_proc_entry (and no barrier needed).
- */
- vlsi_proc_root->owner = THIS_MODULE;
- }
ret = pci_register_driver(&vlsi_irda_driver);
diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c
index 7e80aba8a148..31b1cc2b778a 100644
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -4494,7 +4494,6 @@ static int setup_proc_entry( struct net_device *dev,
goto fail;
apriv->proc_entry->uid = proc_uid;
apriv->proc_entry->gid = proc_gid;
- apriv->proc_entry->owner = THIS_MODULE;
/* Setup the StatsDelta */
entry = proc_create_data("StatsDelta",