Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 28 Apr 2010 09:48:52 -0400 | From | Vivek Goyal <> | Subject | Re: CFQ is broken for CONFIG_BLK_CGROUP=y, CFQ_GROUP_IOSCHED=n |
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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
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