lkml.org 
[lkml]   [2014]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] cgroup: add a validation check to cgroup_add_cftyps()
On Mon, Feb 17, 2014 at 10:41:50AM +0800, Li Zefan wrote:
> Fengguang reported this bug:
>
> BUG: unable to handle kernel NULL pointer dereference at 0000003c
> IP: [<cc90b4ad>] cgroup_cfts_commit+0x27/0x1c1
> ...
> Call Trace:
> [<cc9d1129>] ? kmem_cache_alloc_trace+0x33f/0x3b7
> [<cc90c6fc>] cgroup_add_cftypes+0x8f/0xca
> [<cd78b646>] cgroup_init+0x6a/0x26a
> [<cd764d7d>] start_kernel+0x4d7/0x57a
> [<cd7642ef>] i386_start_kernel+0x92/0x96
>
> This happens in a corner case. If CGROUP_SCHED=y but CFS_BANDWIDTH=n &&
> FAIR_GROUP_SCHED=n && RT_GROUP_SCHED=n, we have:
>
> cpu_files[] = {
> { } /* terminate */
> }
>
> When we pass cpu_files to cgroup_apply_cftypes(), as cpu_files[0].ss
> is NULL, we'll access NULL pointer.
>
> The bug was introduced by commit de00ffa56ea3132c6013fc8f07133b8a1014cf53
> ("cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes()").
>
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Li Zefan <lizefan@huawei.com>

Applied to cgroup/for-3.15. Thanks.

--
tejun


\
 
 \ /
  Last update: 2014-02-19 18:41    [W:0.035 / U:0.388 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site