1 files changed, 40 insertions, 11 deletions

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index f7718ec685fa..cea8350fbc7e 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -344,6 +344,8 @@ struct device *nd_pfn_create(struct nd_region *nd_region)
 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 {
         u64 checksum, offset;
+        unsigned long align;
+        enum nd_pfn_mode mode;
         struct nd_namespace_io *nsio;
         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
         struct nd_namespace_common *ndns = nd_pfn->ndns;
@@ -386,22 +388,50 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
                 return -ENXIO;
         }
 
+        align = le32_to_cpu(pfn_sb->align);
+        offset = le64_to_cpu(pfn_sb->dataoff);
+        if (align == 0)
+                align = 1UL << ilog2(offset);
+        mode = le32_to_cpu(pfn_sb->mode);
+
         if (!nd_pfn->uuid) {
-                /* from probe we allocate */
+                /*
+                 * When probing a namepace via nd_pfn_probe() the uuid
+                 * is NULL (see: nd_pfn_devinit()) we init settings from
+                 * pfn_sb
+                 */
                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
                 if (!nd_pfn->uuid)
                         return -ENOMEM;
+                nd_pfn->align = align;
+                nd_pfn->mode = mode;
         } else {
-                /* from init we validate */
+                /*
+                 * When probing a pfn / dax instance we validate the
+                 * live settings against the pfn_sb
+                 */
                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
                         return -ENODEV;
+
+                /*
+                 * If the uuid validates, but other settings mismatch
+                 * return EINVAL because userspace has managed to change
+                 * the configuration without specifying new
+                 * identification.
+                 */
+                if (nd_pfn->align != align || nd_pfn->mode != mode) {
+                        dev_err(&nd_pfn->dev,
+                                        "init failed, settings mismatch\n");
+                        dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
+                                        nd_pfn->align, align, nd_pfn->mode,
+                                        mode);
+                        return -EINVAL;
+                }
         }
 
-        if (nd_pfn->align == 0)
-                nd_pfn->align = le32_to_cpu(pfn_sb->align);
-        if (nd_pfn->align > nvdimm_namespace_capacity(ndns)) {
+        if (align > nvdimm_namespace_capacity(ndns)) {
                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
-                                nd_pfn->align, nvdimm_namespace_capacity(ndns));
+                                align, nvdimm_namespace_capacity(ndns));
                 return -EINVAL;
         }
 
@@ -411,7 +441,6 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
          * namespace has changed since the pfn superblock was
          * established.
          */
-        offset = le64_to_cpu(pfn_sb->dataoff);
         nsio = to_nd_namespace_io(&ndns->dev);
         if (offset >= resource_size(&nsio->res)) {
                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
@@ -419,10 +448,11 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
                 return -EBUSY;
         }
 
-        if ((nd_pfn->align && !IS_ALIGNED(offset, nd_pfn->align))
+        if ((align && !IS_ALIGNED(offset, align))
                         || !IS_ALIGNED(offset, PAGE_SIZE)) {
-                dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
-                                offset);
+                dev_err(&nd_pfn->dev,
+                                "bad offset: %#llx dax disabled align: %#lx\n",
+                                offset, align);
                 return -ENXIO;
         }
 
@@ -502,7 +532,6 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
         res->start += start_pad;
         res->end -= end_trunc;
 
-        nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
         if (nd_pfn->mode == PFN_MODE_RAM) {
                 if (offset < SZ_8K)
                         return ERR_PTR(-EINVAL);