Commit 6acd7d5ef264d8e9a8988cebf6eeb3567eaf60c6 upstream.
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 --- drivers/nvdimm/namespace_devs.c | 17 +++++++++++++++++ drivers/nvdimm/pfn.h | 12 ++++++++++++ drivers/nvdimm/pfn_devs.c | 32 +++++++++++++++++++++++++++++--- 3 files changed, 58 insertions(+), 3 deletions(-)
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c index cca0a3ba1d2c..b2db15250e0d 100644 --- a/drivers/nvdimm/namespace_devs.c +++ b/drivers/nvdimm/namespace_devs.c @@ -10,6 +10,7 @@ #include <linux/nd.h> #include "nd-core.h" #include "pmem.h" +#include "pfn.h" #include "nd.h"
static void namespace_io_release(struct device *dev) @@ -1735,6 +1736,22 @@ struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev) return ERR_PTR(-ENODEV); }
+ /* + * Note, alignment validation for fsdax and devdax mode + * namespaces happens in nd_pfn_validate() where infoblock + * padding parameters can be applied. + */ + if (pmem_should_map_pages(dev)) { + struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); + struct resource *res = &nsio->res; + + if (!IS_ALIGNED(res->start | (res->end + 1), + memremap_compat_align())) { + dev_err(&ndns->dev, "%pr misaligned, unable to map\n", res); + return ERR_PTR(-EOPNOTSUPP); + } + } + if (is_namespace_pmem(&ndns->dev)) { struct nd_namespace_pmem *nspm;
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 */ diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 6e5b042f453e..18a2602d93e7 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -445,6 +445,7 @@ static bool nd_supported_alignment(unsigned long align) int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) { u64 checksum, offset; + struct resource *res; enum nd_pfn_mode mode; struct nd_namespace_io *nsio; unsigned long align, start_pad; @@ -577,13 +578,14 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) * established. */ nsio = to_nd_namespace_io(&ndns->dev); - if (offset >= resource_size(&nsio->res)) { + res = &nsio->res; + if (offset >= resource_size(res)) { dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n", dev_name(&ndns->dev)); return -EOPNOTSUPP; }
- if ((align && !IS_ALIGNED(nsio->res.start + offset + start_pad, align)) + if ((align && !IS_ALIGNED(res->start + offset + start_pad, align)) || !IS_ALIGNED(offset, PAGE_SIZE)) { dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled align: %#lx\n", @@ -591,6 +593,18 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) return -EOPNOTSUPP; }
+ if (!IS_ALIGNED(res->start + le32_to_cpu(pfn_sb->start_pad), + memremap_compat_align())) { + dev_err(&nd_pfn->dev, "resource start misaligned\n"); + return -EOPNOTSUPP; + } + + if (!IS_ALIGNED(res->end + 1 - le32_to_cpu(pfn_sb->end_trunc), + memremap_compat_align())) { + dev_err(&nd_pfn->dev, "resource end misaligned\n"); + return -EOPNOTSUPP; + } + return 0; } EXPORT_SYMBOL(nd_pfn_validate); @@ -754,7 +768,19 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) start = nsio->res.start; size = resource_size(&nsio->res); npfns = PHYS_PFN(size - SZ_8K); - align = max(nd_pfn->align, SUBSECTION_SIZE); + align = max(nd_pfn->align, memremap_compat_align()); + + /* + * When @start is misaligned fail namespace creation. See + * the 'struct nd_pfn_sb' commentary on why ->start_pad is not + * an option. + */ + if (!IS_ALIGNED(start, memremap_compat_align())) { + dev_err(&nd_pfn->dev, "%s: start %pa misaligned to %#lx\n", + dev_name(&ndns->dev), &start, + memremap_compat_align()); + return -EINVAL; + } end_trunc = start + size - ALIGN_DOWN(start + size, align); if (nd_pfn->mode == PFN_MODE_PMEM) { /*