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libnvdimm/namespace: Enforce memremap_compat_align()

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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: a3619190d6 ("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>
This commit is contained in:
Dan Williams 2020-02-27 21:39:23 -08:00
parent b2ba7e91fa
commit 6acd7d5ef2
3 changed files with 58 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/nvdimm/namespace_devs.c
View File

@ -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)
@ -1739,6 +1740,22 @@ 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;

12
drivers/nvdimm/pfn.h
View File

@ -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 */

32
drivers/nvdimm/pfn_devs.c
View File

@ -446,6 +446,7 @@ 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;
@ -578,13 +579,14 @@ 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",
@ -592,6 +594,18 @@ 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);
@ -750,7 +764,19 @@ 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) {
/*