Re: [PATCH -next] mtd: ubi: wl: Fix error return code in ubi_wl_init()

From: Boris Brezillon
Date: Thu Jan 18 2018 - 10:35:01 EST


On Thu, 18 Jan 2018 15:11:32 +0100
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote:

> On Thu, 18 Jan 2018 15:08:01 +0100
> Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On Thu, 18 Jan 2018 14:05:05 +0000
> > Wei Yongjun <weiyongjun1@xxxxxxxxxx> wrote:
> >
> > > Fix to return error code -ENOMEM from the kmem_cache_alloc() error
> > > handling case instead of 0, as done elsewhere in this function.
> >
> > I guess you've used a static analysis code to detect this problem, can
> > you name it in the commit message, and paste the error/warning message
> > it reported next time you submit this kind of patch.
> >
> > >
> > > Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> >
> > NAck. I you read the code you'll see that err is initialized to -ENOMEM
> > here [1], so these changes are actually not needed.
>
> Sorry, just realized I was wrong. It seems that err can be overridden by
> [2]. So this patch is indeed fixing a real problem.
>
> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>

Oh, and you can add:

Fixes: f78e5623f45b ("ubi: fastmap: Erase outdated anchor PEBs during attach")

>
> >
> > > ---
> > > drivers/mtd/ubi/wl.c | 8 ++++++--
> > > 1 file changed, 6 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
> > > index 77ab49f..2052a64 100644
> > > --- a/drivers/mtd/ubi/wl.c
> > > +++ b/drivers/mtd/ubi/wl.c
> > > @@ -1617,8 +1617,10 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
> > > cond_resched();
> > >
> > > e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
> > > - if (!e)
> > > + if (!e) {
> > > + err = -ENOMEM;
> > > goto out_free;
> > > + }
> > >
> > > e->pnum = aeb->pnum;
> > > e->ec = aeb->ec;
> > > @@ -1637,8 +1639,10 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
> > > cond_resched();
> > >
> > > e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
> > > - if (!e)
> > > + if (!e) {
> > > + err = -ENOMEM;
> > > goto out_free;
> > > + }
> > >
> > > e->pnum = aeb->pnum;
> > > e->ec = aeb->ec;
> > >
> >
> > [1]https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/mtd/ubi/wl.c?h=next-20180118#n1596
>
> [2]https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/mtd/ubi/wl.c?h=next-20180118#n1609
>
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