Re: Racy manipulation of task_struct->flags in cgroups code causes hard to reproduce kernel panics

[Kees Cook]

On Sat, Sep 20, 2014 at 7:30 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Sat, Sep 20, 2014 at 01:55:54PM +0800, Zefan Li wrote:
>> We should make the updating of this flag atomic.
>
>>  /* Per-process atomic flags. */
>>  #define PFA_NO_NEW_PRIVS 0x00000001  /* May not gain new privileges. */
>> +#define PFA_SPREAD_PAGE  0x00000002  /* Spread page cache over cpuset */
>> +#define PFA_SPREAD_SLAB  0x00000004  /* Spread some slab caches over cpuset */
>
> Ooh, I was not ware we had those.. /me checks where that came from. Hmm
> weird, while I did get that patch it had a seccomp prefix when landing
> in my inbox so I ignored it. However the commit has a sched prefix
> (which I would not have ignored). Dubious things happened here.

The series went through a lot of revisions, so it probably gained the
sched prefix later in its life. Is there anything that needs changing
about how this has been implemented?

-Kees

-- 
Kees Cook
Chrome OS Security
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