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

From: Peter Zijlstra
Date: Sat Sep 20 2014 - 10:30:29 EST


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.


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