Fix race between proc_get_inode() and remove_proc_entry()
proc_lookup remove_proc_entry
=========== =================
lock_kernel();
spin_lock(&proc_subdir_lock);
[find PDE with refcount 0]
spin_unlock(&proc_subdir_lock);
spin_lock(&proc_subdir_lock);
[find PDE with refcount 0]
[check refcount and free PDE]
spin_unlock(&proc_subdir_lock);
proc_get_inode:
de_get(de); /* boom */
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 775fb21..22a08ff 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -398,6 +398,7 @@
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 @@
d_add(dentry, inode);
return NULL;
}
+ de_put(de);
return ERR_PTR(error);
}