From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: Racy manipulation of task_struct->flags in cgroups code causes hard to reproduce kernel panics Date: Sat, 20 Sep 2014 16:30:12 +0200 Message-ID: <20140920143012.GL2832@worktop.localdomain> References: <201409192053.IHJ35462.JLOMOSOFFVtQFH@I-love.SAKURA.ne.jp> <541D16EA.70407@huawei.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <541D16EA.70407-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Zefan Li Cc: Tetsuo Handa , mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fernando_b1-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org, keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org 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.