4.9-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
commit 966d23a006ca7b44ac8cf4d0c96b19785e0c3da0 upstream.
The UEFI 2.7 specification sets expectations that the 'updating' flag is eventually cleared. To date, the libnvdimm core has never adhered to that protocol. The policy of the core matches the policy of other multi-device info-block formats like MD-Software-RAID that expect administrator intervention on inconsistent info-blocks, not automatic invalidation.
However, some pre-boot environments may unfortunately attempt to "clean up" the labels and invalidate a set when it fails to find at least one "non-updating" label in the set. Clear the updating flag after set updates to minimize the window of vulnerability to aggressive pre-boot environments.
Ideally implementations would not write to the label area outside of creating namespaces.
Note that this only minimizes the window, it does not close it as the system can still crash while clearing the flag and the set can be subsequently deleted / invalidated by the pre-boot environment.
Fixes: f524bf271a5c ("libnvdimm: write pmem label set") Cc: stable@vger.kernel.org Cc: Kelly Couch kelly.j.couch@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/nvdimm/label.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
--- a/drivers/nvdimm/label.c +++ b/drivers/nvdimm/label.c @@ -492,7 +492,7 @@ static unsigned long nd_label_offset(str
static int __pmem_label_update(struct nd_region *nd_region, struct nd_mapping *nd_mapping, struct nd_namespace_pmem *nspm, - int pos) + int pos, unsigned long flags) { u64 cookie = nd_region_interleave_set_cookie(nd_region); struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); @@ -530,7 +530,7 @@ static int __pmem_label_update(struct nd memcpy(nd_label->uuid, nspm->uuid, NSLABEL_UUID_LEN); if (nspm->alt_name) memcpy(nd_label->name, nspm->alt_name, NSLABEL_NAME_LEN); - nd_label->flags = __cpu_to_le32(NSLABEL_FLAG_UPDATING); + nd_label->flags = __cpu_to_le32(flags); nd_label->nlabel = __cpu_to_le16(nd_region->ndr_mappings); nd_label->position = __cpu_to_le16(pos); nd_label->isetcookie = __cpu_to_le64(cookie); @@ -922,13 +922,13 @@ static int del_labels(struct nd_mapping int nd_pmem_namespace_label_update(struct nd_region *nd_region, struct nd_namespace_pmem *nspm, resource_size_t size) { - int i; + int i, rc;
for (i = 0; i < nd_region->ndr_mappings; i++) { struct nd_mapping *nd_mapping = &nd_region->mapping[i]; struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); struct resource *res; - int rc, count = 0; + int count = 0;
if (size == 0) { rc = del_labels(nd_mapping, nspm->uuid); @@ -946,7 +946,20 @@ int nd_pmem_namespace_label_update(struc if (rc < 0) return rc;
- rc = __pmem_label_update(nd_region, nd_mapping, nspm, i); + rc = __pmem_label_update(nd_region, nd_mapping, nspm, i, + NSLABEL_FLAG_UPDATING); + if (rc) + return rc; + } + + if (size == 0) + return 0; + + /* Clear the UPDATING flag per UEFI 2.7 expectations */ + for (i = 0; i < nd_region->ndr_mappings; i++) { + struct nd_mapping *nd_mapping = &nd_region->mapping[i]; + + rc = __pmem_label_update(nd_region, nd_mapping, nspm, i, 0); if (rc) return rc; }