nfit: fix smatch "use after null check" report

drivers/acpi/nfit.c:1224 acpi_nfit_blk_region_enable()
         error: we previously assumed 'nfit_mem' could be null (see line 1223)

drivers/acpi/nfit.c
  1222          nfit_mem = nvdimm_provider_data(nvdimm);
  1223          if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
                     ^^^^^^^^
Check.

  1224                  dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
  1225                                  nfit_mem ? "" : " nfit_mem",
  1226                                  nfit_mem->dcr ? "" : " dcr",
                                        ^^^^^^^^^^^^^
Unchecked dereference.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 2161fa178c8d07a5a66d605ca8dbb6a42beea4db..a20b7c883ca0709a4e3c94787f5e1fcc5ed2c922 100644 (file)
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -1223,8 +1223,8 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
        if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
                dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
                                nfit_mem ? "" : " nfit_mem",
-                               nfit_mem->dcr ? "" : " dcr",
-                               nfit_mem->bdw ? "" : " bdw");
+                               (nfit_mem && nfit_mem->dcr) ? "" : " dcr",
+                               (nfit_mem && nfit_mem->bdw) ? "" : " bdw");
                return -ENXIO;
        }