The pmem driver on PowerPC crashes with the following signature when instantiating misaligned namespaces that map their capacity via memremap_pages().
BUG: Unable to handle kernel data access at 0xc001000406000000 Faulting instruction address: 0xc000000000090790 NIP [c000000000090790] arch_add_memory+0xc0/0x130 LR [c000000000090744] arch_add_memory+0x74/0x130 Call Trace: arch_add_memory+0x74/0x130 (unreliable) memremap_pages+0x74c/0xa30 devm_memremap_pages+0x3c/0xa0 pmem_attach_disk+0x188/0x770 nvdimm_bus_probe+0xd8/0x470 With the assumption that only memremap_pages() has alignment constraints, enforce memremap_compat_align() for pmem_should_map_pages(), nd_pfn, or nd_dax cases. Reported-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> Cc: Jeff Moyer <jmo...@redhat.com> Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> Link: https://lore.kernel.org/r/158041477336.3889308.4581652885008605170.st...@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.willi...@intel.com> --- drivers/nvdimm/namespace_devs.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c index 032dc61725ff..aff1f32fdb4f 100644 --- a/drivers/nvdimm/namespace_devs.c +++ b/drivers/nvdimm/namespace_devs.c @@ -1739,6 +1739,16 @@ struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev) return ERR_PTR(-ENODEV); } + if (pmem_should_map_pages(dev) || nd_pfn || nd_dax) { + struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); + resource_size_t start = nsio->res.start; + + if (!IS_ALIGNED(start | size, memremap_compat_align())) { + dev_dbg(&ndns->dev, "misaligned, unable to map\n"); + return ERR_PTR(-EOPNOTSUPP); + } + } + if (is_namespace_pmem(&ndns->dev)) { struct nd_namespace_pmem *nspm;