2020-10-11 18:06:37

by Hannes Reinecke

Subject: Re: [PATCH] block: switch to pr_warn() in __device_add_disk()

On 10/11/20 3:03 PM, Rustam Kovhaev wrote:
> syzbot triggered a warning while fuzzing with failslab fault injection
> enabled
> let's convert WARN_ON() to pr_warn()
>
> Reported-and-tested-by: [email protected]
> Link: https://syzkaller.appspot.com/bug?extid=f41893bb8c45cd18cf08
> Signed-off-by: Rustam Kovhaev <[email protected]>
> ---
> block/genhd.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 99c64641c314..be9ce35cf0fe 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -822,7 +822,8 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
> /* Register BDI before referencing it from bdev */
> dev->devt = devt;
> ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
> - WARN_ON(ret);
> + if (ret)
> + pr_warn("%s: failed to register backing dev info\n", disk->disk_name);
> bdi_set_owner(bdi, dev);
> blk_register_region(disk_devt(disk), disk->minors, NULL,
> exact_match, exact_lock, disk);
>
Please, don't. Where is the point in continuing here?
I'd rather have it fixed up properly, either by having a return value to
__device_add_disk() or by allowing the caller to check (eg by checking
GENHD_FL_UP) if the call succeeded.

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
[email protected] +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

2020-10-11 18:09:29

by Rustam Kovhaev

Subject: Re: [PATCH] block: switch to pr_warn() in __device_add_disk()

On Sun, Oct 11, 2020 at 04:53:22PM +0200, Hannes Reinecke wrote:
> On 10/11/20 3:03 PM, Rustam Kovhaev wrote:
> > syzbot triggered a warning while fuzzing with failslab fault injection
> > enabled
> > let's convert WARN_ON() to pr_warn()
> >
> > Reported-and-tested-by: [email protected]
> > Link: https://syzkaller.appspot.com/bug?extid=f41893bb8c45cd18cf08
> > Signed-off-by: Rustam Kovhaev <[email protected]>
> > ---
> > block/genhd.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/block/genhd.c b/block/genhd.c
> > index 99c64641c314..be9ce35cf0fe 100644
> > --- a/block/genhd.c
> > +++ b/block/genhd.c
> > @@ -822,7 +822,8 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
> > /* Register BDI before referencing it from bdev */
> > dev->devt = devt;
> > ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
> > - WARN_ON(ret);
> > + if (ret)
> > + pr_warn("%s: failed to register backing dev info\n", disk->disk_name);
> > bdi_set_owner(bdi, dev);
> > blk_register_region(disk_devt(disk), disk->minors, NULL,
> > exact_match, exact_lock, disk);
> >
> Please, don't. Where is the point in continuing here?
> I'd rather have it fixed up properly, either by having a return value to
> __device_add_disk() or by allowing the caller to check (eg by checking
> GENHD_FL_UP) if the call succeeded.
thank you for the review, it makes sense.