Re: [floppy, blk_peek_request] BUG: scheduling while atomic:kworker/u:0/6/0x10000002

From: Jiri Kosina
Date: Mon Nov 05 2012 - 08:34:08 EST


On Mon, 5 Nov 2012, Jiri Kosina wrote:

> > I got the below oops in Linux 3.7-rc4 and it's bisected down to
> >
> > commit b54e1f88897bcacc2cd359f48ea3b39eaf55f084
> > Author: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
> > Date: Mon Aug 27 20:56:51 2012 -0300
> >
> > floppy: don't call alloc_ordered_workqueue inside the alloc_disk loop
>
> Fengguang,
>
> thanks for the report.
>
> How reliable is the bisection result? (i.e. how reliably are you able to
> trigger this oops?).
>
> I am having a hard time seeing how that particular commit could be causing
> this kind of oops.

Hmm, actually I do see an option how this might happen on machines not
having an actual floppy drive.

Fengguang, does the patch below make any difference for you please?

Thanks.




drivers/block/floppy.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 1c49d71..3b9cc0f 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4329,6 +4329,7 @@ out_unreg_region:
platform_driver_unregister(&floppy_driver);
out_unreg_blkdev:
unregister_blkdev(FLOPPY_MAJOR, "fd");
+ destroy_workqueue(floppy_wq);
out_put_disk:
for (drive = 0; drive < N_DRIVE; drive++) {
if (!disks[drive])
@@ -4340,7 +4341,6 @@ out_put_disk:
}
put_disk(disks[drive]);
}
- destroy_workqueue(floppy_wq);
return err;
}


--
Jiri Kosina
SUSE Labs
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