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

From: Jiri Kosina
Date: Mon Nov 05 2012 - 11:53:36 EST


On Mon, 5 Nov 2012, Vivek Goyal wrote:

> > > Yes, I saw the same thing here, destroy_workqueue should be done before
> > > clearing the queue (blk_cleanup_queue) indeed. user_reset_fdc called
> > > process_fd_request and that scheduled redo_fd_request, that tries to
> > > take the queue already cleaned up in set_next_request I expect.
> > >
> > > >
> > > >
> > > >
> > > >
> > > > 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);
> > >
> > > This should go right after the out_put_disk label, otherwise we may
> > > leak the floppy_wq on early error.
> >
> > Indeed.
> >
> > Fengguang, could you please test with the patch below instead? (it should
> > be functionally equivalent in most of the cases though).
> >
>
> What about floppy_module_exit(). There also we seem to cleanup the queue
> first before flushing and destroying floppy_wq workqueue.

Yup, will fix that up in a final patch once we have confirmation from
Fengguang that it fixes the problem he is seeing.

Thanks,

--
Jiri Kosina
SUSE Labs
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