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

From: Jiri Kosina
Date: Mon Nov 05 2012 - 10:33:30 EST


On Mon, 5 Nov 2012, Herton Ronaldo Krzesinski wrote:

> > Fengguang, does the patch below make any difference for you please?
> >
> > Thanks.
>
> 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).

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..e386d83 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4330,6 +4330,7 @@ out_unreg_region:
out_unreg_blkdev:
unregister_blkdev(FLOPPY_MAJOR, "fd");
out_put_disk:
+ destroy_workqueue(floppy_wq);
for (drive = 0; drive < N_DRIVE; drive++) {
if (!disks[drive])
break;
@@ -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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