lkml.org 
[lkml]   [2010]   [Apr]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: CFQ is broken for CONFIG_BLK_CGROUP=y, CFQ_GROUP_IOSCHED=n
On Wed, Apr 28, 2010 at 04:44:51PM +0400, Dmitry Monakhov wrote:
>
> I've had an oops on kernel boot due to NULL pointer deference
> linux-2.6-block/for-next HEAD:7eaed1226ab411ee5dc8c34fc0d8034e4c98e3c6
> I've enabled CONFIG_BLK_CGROUP, but not CFQ_GROUP_IOSCHED
> In this case cfq_ref_get_cfqg() defined as
> static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
> {
> return NULL;
> }
> So following call trace is simply NOOP
> cfq_set_request()
> rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg);
>
> Which later result in OOPS on bio insertion
> cfq_insert_request
> -> blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,...)
> -> spin_lock_irqsave(&blkg->stats_lock, flags);
>
> Bad commit.
> >From 7f1dc8a2d2f45fc557b27fd56115338b1d34fc24 Mon Sep 17 00:00:00 2001
> From: Vivek Goyal <vgoyal@redhat.com>
> Date: Wed, 21 Apr 2010 17:44:16 +0200
> Subject: [PATCH] blkio: Fix blkio crash during rq stat update

Hi Dmitry,

Thanks for reporting the issue. I am cooking up a patch now.

Vivek


\
 
 \ /
  Last update: 2010-04-28 15:51    [W:0.062 / U:0.496 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site