There are four BKL users in proc: de_put(), proc_lookup_de(),
proc_readdir_de(), proc_root_readdir(),
1) de_put()
-----------
de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL
needed. BKL doesn't matter to possible refcount leak as well.
2) proc_lookup_de()
-------------------
Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is
potentially blocking, all callers of proc_lookup_de() eventually end up
from ->lookup hooks which is protected by directory's ->i_mutex -- BKL
doesn't protect anything.
3) proc_readdir_de()
--------------------
"." and ".." part doesn't need BKL, walking PDE list is under
proc_subdir_lock, calling filldir callback is potentially blocking
because it writes to luserspace. All proc_readdir_de() callers
eventually come from ->readdir hook which is under directory's
->i_mutex -- BKL doesn't protect anything.
4) proc_root_readdir_de()
-------------------------
proc_root_readdir_de is ->readdir hook, see (3).
Since readdir hooks doesn't use BKL anymore, switch to
generic_file_llseek, since it also takes directory's i_mutex.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/mount.h>
-#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/namei.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/namei.h>
struct inode *inode = NULL;
int error = -ENOENT;
struct inode *inode = NULL;
int error = -ENOENT;
spin_lock(&proc_subdir_lock);
for (de = de->subdir; de ; de = de->next) {
if (de->namelen != dentry->d_name.len)
spin_lock(&proc_subdir_lock);
for (de = de->subdir; de ; de = de->next) {
if (de->namelen != dentry->d_name.len)
}
spin_unlock(&proc_subdir_lock);
out_unlock:
}
spin_unlock(&proc_subdir_lock);
out_unlock:
if (inode) {
dentry->d_op = &proc_dentry_operations;
if (inode) {
dentry->d_op = &proc_dentry_operations;
struct inode *inode = filp->f_path.dentry->d_inode;
int ret = 0;
struct inode *inode = filp->f_path.dentry->d_inode;
int ret = 0;
ino = inode->i_ino;
i = filp->f_pos;
switch (i) {
ino = inode->i_ino;
i = filp->f_pos;
switch (i) {
spin_unlock(&proc_subdir_lock);
}
ret = 1;
spin_unlock(&proc_subdir_lock);
}
ret = 1;
* the /proc directory.
*/
static const struct file_operations proc_dir_operations = {
* the /proc directory.
*/
static const struct file_operations proc_dir_operations = {
+ .llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = proc_readdir,
};
.read = generic_read_dir,
.readdir = proc_readdir,
};
*/
void de_put(struct proc_dir_entry *de)
{
*/
void de_put(struct proc_dir_entry *de)
{
if (!atomic_read(&de->count)) {
printk("de_put: entry %s already free!\n", de->name);
if (!atomic_read(&de->count)) {
printk("de_put: entry %s already free!\n", de->name);
return;
}
if (atomic_dec_and_test(&de->count))
free_proc_entry(de);
return;
}
if (atomic_dec_and_test(&de->count))
free_proc_entry(de);
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
-#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
}
const struct file_operations proc_net_operations = {
}
const struct file_operations proc_net_operations = {
+ .llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = proc_tgid_net_readdir,
};
.read = generic_read_dir,
.readdir = proc_tgid_net_readdir,
};
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
-#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
unsigned int nr = filp->f_pos;
int ret;
unsigned int nr = filp->f_pos;
int ret;
if (nr < FIRST_PROCESS_ENTRY) {
int error = proc_readdir(filp, dirent, filldir);
if (nr < FIRST_PROCESS_ENTRY) {
int error = proc_readdir(filp, dirent, filldir);
- if (error <= 0) {
- unlock_kernel();
filp->f_pos = FIRST_PROCESS_ENTRY;
}
filp->f_pos = FIRST_PROCESS_ENTRY;
}
ret = proc_pid_readdir(filp, dirent, filldir);
return ret;
ret = proc_pid_readdir(filp, dirent, filldir);
return ret;