4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Toshi Kani <toshi.kani@xxxxxxx> commit 23fbd7c70aec7600e3227eb24259fc55bf6e4881 upstream. A NULL pointer reference kernel bug was observed when acpi_nfit_add_dimm() called in acpi_nfit_register_dimms() failed. This error path does not set nfit_mem->nvdimm, but the 2nd list_for_each_entry() loop in the function assumes it's always set. Add a check to nfit_mem->nvdimm. Fixes: ba9c8dd3c222 ("acpi, nfit: add dimm device notification support") Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/nfit/core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -1618,6 +1618,9 @@ static int acpi_nfit_register_dimms(stru struct kernfs_node *nfit_kernfs; nvdimm = nfit_mem->nvdimm; + if (!nvdimm) + continue; + nfit_kernfs = sysfs_get_dirent(nvdimm_kobj(nvdimm)->sd, "nfit"); if (nfit_kernfs) nfit_mem->flags_attr = sysfs_get_dirent(nfit_kernfs,