Messages in this thread | | | Date | Tue, 24 Jul 2012 17:35:30 +0400 | From | "Maxim V. Patlasov" <> | Subject | Re: [REGRESSION] [PATCH] block: uninitialized ioc->nr_tasks triggers WARN_ON |
| |
Hi Tejun,
07/18/2012 02:24 AM, Tejun Heo пишет: > Hello, Olof. > > On Tue, Jul 17, 2012 at 02:36:43PM -0700, Olof Johansson wrote: >> It seems like the init of ioc->nr_tasks was removed in that patch, >> so it starts out at 0 instead of 1. >> >> Tejun, is the right thing here to add back the init, or should something else >> be done? >> >> The below patch removes the warning, but I haven't done any more extensive >> testing on it. >> >> >> Signed-off-by: Olof Johansson <olof@lixom.net> > Right, the patch shouldn't have replaced the init. > > Acked-by: Tejun Heo <tj@kernel.org> > > Fortunately, the effect of the bug is limited. ioc->nr_tasks only > used to veto block cgroup migration if a task has ioc which is shared > by multiple tasks. Currently, the only known program using CLONE_IO > is dump and even if somebody migrates some threads of a single dump > instance to a different block cgroup, the result won't be catastrophic > although block cgroup policies would become ambiguous. IMHO, it > should be okay to route this through -stable after 3.5. Jens?
Please notice that annoying WARN_ON comes from world-visible ioc_task_link(). So any third-party module using ioc_task_link() ends up in that clutter in logs. E.g. OpenVZ ploop block-device uses ioc_task_link().
Thanks, Maxim
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |