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Commit 33d283be authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cgroups: fix a serious bug in cgroupstats 



Try this, and you'll get oops immediately:
 # cd Documentation/accounting/
 # gcc -o getdelays getdelays.c
 # mount -t cgroup -o debug xxx /mnt
 # ./getdelays -C /mnt/tasks

Because a normal file's dentry->d_fsdata is a pointer to struct cftype,
not struct cgroup.

After the patch, it returns EINVAL if we try to get cgroupstats
from a normal file.

Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarPaul Menage <menage@google.com>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x, 2.6.27.x]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ea7e743e

kernel/cgroup.c

+5 −2
Original line number Diff line number Diff line
@@ -2039,10 +2039,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) 
	struct cgroup *cgrp;

	struct cgroup_iter it;

	struct task_struct *tsk;



	/*

	 * Validate dentry by checking the superblock operations

	 * Validate dentry by checking the superblock operations,

	 * and make sure it's a directory.

	 */

	if (dentry->d_sb->s_op != &cgroup_ops)

	if (dentry->d_sb->s_op != &cgroup_ops ||

	    !S_ISDIR(dentry->d_inode->i_mode))

		 goto err;



	ret = 0;