Re: [PATCH v3] nvme: core: reject invalid LBA data size from Identify Namespace

[Keith Busch]

On Tue, Jun 02, 2026 at 02:10:07PM +0100, John Garry wrote:
> On 15/05/2026 19:58, Chao Shi wrote:
> > +	if (id->lbaf[lbaf].ds < SECTOR_SHIFT ||
> > +	    check_shl_overflow(le64_to_cpu(id->nsze),> +			 id->lbaf[lbaf].ds -
> SECTOR_SHIFT,
> > +			       &capacity)) {
> > +		dev_warn_once(ns->ctrl->device,
> > +			"invalid LBA data size %u, skipping namespace\n",
> > +			id->lbaf[lbaf].ds);
> > +		ret = -ENODEV;
> > +		goto out;
> > +	}
> 
> JFYI, this is giving a C=1 warning:
> 
> drivers/nvme/host/core.c:2411:13: warning: unsigned value that used to  be signed checked against zero?
> drivers/nvme/host/core.c:2411:13: signed value source
> 
> I can't seem to quieten it myself, though.
> 
> BTW, I would have thought that check_shl_overflow would catch
> id->lbaf[lbaf].ds < SECTOR_SHIFT (so that we don't need the extra check).

I see it too. check_shl_overflow has checks that suggest it was
expecting a signed type, as all the < 0 checks don't make sense for
unsigned. The warning seems harmless, but I'd too like to see it
suppressed.

I think it's odd that I'm not seeing a similar error for the similar
usage in generic_check_addressable() from fs/libfs.c. They look the same
to me with respect to the types passed in.