Re: [PATCH rc v4 1/5] iommu/arm-smmu-v3: Add arm_smmu_kdump_adopt_strtab() for kdump

Nicolin Chen
2026-04-30T15:24:39Z

On Thu, Apr 30, 2026 at 08:55:13AM -0300, Jason Gunthorpe wrote:
> On Wed, Apr 29, 2026 at 02:37:50PM -0700, Nicolin Chen wrote:
> > On Wed, Apr 29, 2026 at 12:20:49AM -0700, Nicolin Chen wrote:
> >
> > > +static int arm_smmu_kdump_adopt_strtab_2lvl(struct arm_smmu_device *smmu,
> > > + u32 cfg_reg, dma_addr_t dma)
> > [...]
> > > + for (i = 0; i < num_l1_ents; i++) {
> > > + u64 l2ptr = le64_to_cpu(cfg->l2.l1tab[i].l2ptr);
> >
> > Sashiko pointed out a missing READ_ON here.
>
> ??
>
> There is no concurrency at this point?

You are right. I got confused. I was thinking of an RID-sharing
case where some race might happen and adding READ_ONCE could be
defensive.

A kdump kernel has a very limited use. So, this isn't necessary.

Thanks
Nicolin