From: Jeff Moyer <jmoyer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@lists.01.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
vishal.l.verma@intel.com, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 2/4] libnvdimm/namespace: Enforce memremap_compat_align()
Date: Thu, 13 Feb 2020 16:55:35 -0500 [thread overview]
Message-ID: <x49k14q5ezs.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <158155490897.3343782.14216276134794923581.stgit@dwillia2-desk3.amr.corp.intel.com> (Dan Williams's message of "Wed, 12 Feb 2020 16:48:29 -0800")
Dan Williams <dan.j.williams@intel.com> writes:
> 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.kumar@linux.ibm.com>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> Link: https://lore.kernel.org/r/158041477336.3889308.4581652885008605170.stgit@dwillia2-desk3.amr.corp.intel.com
> Signed-off-by: Dan Williams <dan.j.williams@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;
>
Actually, I take back my ack. :) This prevents a previously working
namespace from being successfully probed/setup. I thought we were only
going to enforce the alignment for a newly created namespace? This should
only check whether the alignment works for the current platform.
-Jeff
next prev parent reply other threads:[~2020-02-13 21:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 0:48 [PATCH v2 0/4] libnvdimm: Cross-arch compatible namespace alignment Dan Williams
2020-02-13 0:48 ` [PATCH v2 1/4] mm/memremap_pages: Introduce memremap_compat_align() Dan Williams
2020-02-13 16:57 ` Jeff Moyer
2020-02-13 18:26 ` Dan Williams
2020-02-14 3:26 ` Aneesh Kumar K.V
2020-02-14 20:59 ` Jeff Moyer
2020-02-14 23:05 ` Dan Williams
2020-02-13 0:48 ` [PATCH v2 2/4] libnvdimm/namespace: Enforce memremap_compat_align() Dan Williams
2020-02-13 19:16 ` Jeff Moyer
2020-02-13 21:55 ` Jeff Moyer [this message]
2020-02-13 22:43 ` Dan Williams
2020-02-14 16:44 ` Jeff Moyer
2020-02-14 16:55 ` Aneesh Kumar K.V
2020-02-13 0:48 ` [PATCH v2 3/4] libnvdimm/region: Introduce NDD_LABELING Dan Williams
2020-02-13 19:12 ` Jeff Moyer
2020-02-13 0:48 ` [PATCH v2 4/4] libnvdimm/region: Introduce an 'align' attribute Dan Williams
2020-02-14 20:19 ` Jeff Moyer
2020-02-14 21:03 ` [PATCH v2 0/4] libnvdimm: Cross-arch compatible namespace alignment Jeff Moyer
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