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authorDan Williams <dan.j.williams@intel.com>2020-02-28 08:39:23 +0300
committerDan Williams <dan.j.williams@intel.com>2020-03-17 22:23:21 +0300
commit6acd7d5ef264d8e9a8988cebf6eeb3567eaf60c6 (patch)
tree38b3ebe83d3d4dbd380c7da6e7769f8a17c92463 /drivers/nvdimm/pfn.h
parentb2ba7e91fa81bec9b64c47ab852145559cad2b68 (diff)
downloadlinux-6acd7d5ef264d8e9a8988cebf6eeb3567eaf60c6.tar.xz
libnvdimm/namespace: Enforce memremap_compat_align()
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, and nd_dax cases. This includes preventing the creation of namespaces where the base address is misaligned and cases there infoblock padding parameters are invalid. Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Jeff Moyer <jmoyer@redhat.com> Fixes: a3619190d62e ("libnvdimm/pfn: stop padding pmem namespaces to section alignment") Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm/pfn.h')
-rw-r--r--drivers/nvdimm/pfn.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index acb19517f678..37cb1b8a2a39 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -24,6 +24,18 @@ struct nd_pfn_sb {
__le64 npfns;
__le32 mode;
/* minor-version-1 additions for section alignment */
+ /**
+ * @start_pad: Deprecated attribute to pad start-misaligned namespaces
+ *
+ * start_pad is deprecated because the original definition did
+ * not comprehend that dataoff is relative to the base address
+ * of the namespace not the start_pad adjusted base. The result
+ * is that the dax path is broken, but the block-I/O path is
+ * not. The kernel will no longer create namespaces using start
+ * padding, but it still supports block-I/O for legacy
+ * configurations mainly to allow a backup, reconfigure the
+ * namespace, and restore flow to repair dax operation.
+ */
__le32 start_pad;
__le32 end_trunc;
/* minor-version-2 record the base alignment of the mapping */