Fix race between proc_get_inode() and remove_proc_entry()

[mirror_ubuntu-zesty-kernel.git] / fs / proc / generic.c

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 853cb877d5f3e42b2c617f972a6292bc03912ee8..22a08ff3475de39b203806a55076cc02e8a13dfc 100644 (file)
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -32,14 +32,14 @@ static loff_t proc_file_lseek(struct file *, loff_t, int);
 
 DEFINE_SPINLOCK(proc_subdir_lock);
 
-int proc_match(int len, const char *name, struct proc_dir_entry *de)
+static int proc_match(int len, const char *name, struct proc_dir_entry *de)
 {
        if (de->namelen != len)
                return 0;
        return !memcmp(name, de->name, len);
 }
 
-static struct file_operations proc_file_operations = {
+static const struct file_operations proc_file_operations = {
        .llseek         = proc_file_lseek,
        .read           = proc_file_read,
        .write          = proc_file_write,
@@ -265,7 +265,7 @@ static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
        return 0;
 }
 
-static struct inode_operations proc_file_inode_operations = {
+static const struct inode_operations proc_file_inode_operations = {
        .setattr        = proc_notify_change,
 };
 
@@ -357,7 +357,7 @@ static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
        return NULL;
 }
 
-static struct inode_operations proc_link_inode_operations = {
+static const struct inode_operations proc_link_inode_operations = {
        .readlink       = generic_readlink,
        .follow_link    = proc_follow_link,
 };
@@ -398,6 +398,7 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
                        if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
                                unsigned int ino = de->low_ino;
 
+                               de_get(de);
                                spin_unlock(&proc_subdir_lock);
                                error = -EINVAL;
                                inode = proc_get_inode(dir->i_sb, ino, de);
@@ -414,6 +415,7 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
                d_add(dentry, inode);
                return NULL;
        }
+       de_put(de);
        return ERR_PTR(error);
 }
 
@@ -497,7 +499,7 @@ out:        unlock_kernel();
  * use the in-memory "struct proc_dir_entry" tree to parse
  * the /proc directory.
  */
-static struct file_operations proc_dir_operations = {
+static const struct file_operations proc_dir_operations = {
        .read                   = generic_read_dir,
        .readdir                = proc_readdir,
 };
@@ -505,7 +507,7 @@ static struct file_operations proc_dir_operations = {
 /*
  * proc directories can do almost nothing..
  */
-static struct inode_operations proc_dir_inode_operations = {
+static const struct inode_operations proc_dir_inode_operations = {
        .lookup         = proc_lookup,
        .getattr        = proc_getattr,
        .setattr        = proc_notify_change,