| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.13 045/110] libnvdimm, namespace: fix btt claim class crash | Date | Tue, 3 Oct 2017 14:29:07 +0200 |
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4.13-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams <dan.j.williams@intel.com>
commit 33a56086712561b8b9cdc881e0317f4c36861f72 upstream.
Maurice reports:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 IP: holder_class_store+0x253/0x2b0 [libnvdimm]
...while trying to reconfigure an NVDIMM-N namespace into 'sector' / 'btt' mode. The crash points to this line:
(gdb) li *(holder_class_store+0x253) 0x7773 is in holder_class_store (drivers/nvdimm/namespace_devs.c:1420). 1415 for (i = 0; i < nd_region->ndr_mappings; i++) { 1416 struct nd_mapping *nd_mapping = &nd_region->mapping[i]; 1417 struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); 1418 struct nd_namespace_index *nsindex; 1419 1420 nsindex = to_namespace_index(ndd, ndd->ns_current);
...where we are failing because ndd is NULL due to NVDIMM-N dimms not supporting labels.
Long story short, default to the BTTv1 format in the label-less / NVDIMM-N case.
Fixes: 14e494542636 ("libnvdimm, btt: BTT updates for UEFI 2.7 format") Cc: Vishal Verma <vishal.l.verma@intel.com> Reported-by: Maurice A. Saldivar <maurice.a.saldivar@hpe.com> Tested-by: Maurice A. Saldivar <maurice.a.saldivar@hpe.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/nvdimm/namespace_devs.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/drivers/nvdimm/namespace_devs.c +++ b/drivers/nvdimm/namespace_devs.c @@ -1417,6 +1417,15 @@ static int btt_claim_class(struct device struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); struct nd_namespace_index *nsindex; + /* + * If any of the DIMMs do not support labels the only + * possible BTT format is v1. + */ + if (!ndd) { + loop_bitmask = 0; + break; + } + nsindex = to_namespace_index(ndd, ndd->ns_current); if (nsindex == NULL) loop_bitmask |= 1;
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