Re: [PATCH] mtd: partitions: Handle add_mtd_device() failures gracefully

From: Boris Brezillon
Date: Thu Apr 26 2018 - 13:53:24 EST


Hi Geert,

Sorry for the late reply.

On Tue, 10 Apr 2018 15:26:20 +0200
Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:

> Hi Marek,
>
> On Mon, Apr 9, 2018 at 11:59 PM, Marek Vasut <marek.vasut@xxxxxxxxx> wrote:
> > On 04/09/2018 02:25 PM, Geert Uytterhoeven wrote:
> >> Currently add_mtd_device() failures are plainly ignored, which may lead
> >> to kernel crashes later.
>
> >> Fix this by ignoring and freeing partitions that failed to add in
> >> add_mtd_partitions(). The same issue is present in mtd_add_partition(),
> >> so fix that as well.
> >>
> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> >> ---
> >> I don't know if it is worthwhile factoring out the common handling.
> >>
> >> Should allocate_partition() fail instead? There's a comment saying
> >> "let's register it anyway to preserve ordering".
>
> >> --- a/drivers/mtd/mtdpart.c
> >> +++ b/drivers/mtd/mtdpart.c
>
> >> @@ -746,7 +753,15 @@ int add_mtd_partitions(struct mtd_info *master,
> >> list_add(&slave->list, &mtd_partitions);
> >> mutex_unlock(&mtd_partitions_mutex);
> >>
> >> - add_mtd_device(&slave->mtd);
> >> + ret = add_mtd_device(&slave->mtd);
> >> + if (ret) {
> >> + mutex_lock(&mtd_partitions_mutex);
> >> + list_del(&slave->list);
> >> + mutex_unlock(&mtd_partitions_mutex);
> >> + free_partition(slave);
> >> + continue;
> >> + }
> >
> > Why is the partition even in the list in the first place ? Can we avoid
> > adding it rather than adding and removing it ?
>
> Hence my question "Should allocate_partition() fail instead?".

I'd prefer this option too. Can you prepare a new version doing that?

Thanks,

Boris