4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Williams <dan.j.willi...@intel.com>
commit 6a84fb4b4e439a8ef0ce19ec7e7661ad76f655c9 upstream.
If the dax_pmem driver is passed a resource that is already busy the
driver probe attempt should fail with a message like the following:
dax_pmem dax0.1: could not reserve region [mem 0x100000000-0x11fffffff]
However, if we do not catch the error we crash for the obvious reason of
accessing memory that is not mapped.
BUG: unable to handle kernel paging request at ffffc90020001000
IP: [<ffffffff81496712>] __memcpy+0x12/0x20
[..]
Call Trace:
[<ffffffff815c4960>] ? nsio_rw_bytes+0x60/0x180
[<ffffffff815c6045>] nd_pfn_validate+0x75/0x320
[<ffffffff815c63a9>] nvdimm_setup_pfn+0xb9/0x5d0
[<ffffffff815c48ef>] ? devm_nsio_enable+0xff/0x110
[<ffffffff815cb699>] dax_pmem_probe+0x59/0x260
Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory")
Reported-by: Dave Hansen <dave.han...@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/dax/pmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -77,7 +77,9 @@ static int dax_pmem_probe(struct device
nsio = to_nd_namespace_io(&ndns->dev);
/* parse the 'pfn' info block via ->rw_bytes */
- devm_nsio_enable(dev, nsio);
+ rc = devm_nsio_enable(dev, nsio);
+ if (rc)
+ return rc;
altmap = nvdimm_setup_pfn(nd_pfn, &res, &__altmap);
if (IS_ERR(altmap))
return PTR_ERR(altmap);
