Re: Racy manipulation of task_struct->flags in cgroups code causes hard to reproduce kernel panics
From: Peter Zijlstra
Date: Sat Sep 20 2014 - 14:04:34 EST
On Sat, Sep 20, 2014 at 10:15:50AM -0700, Kees Cook wrote:
> 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?
No, don't think so, just got surprised.
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