4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Jiang <dave.jiang@xxxxxxxxx> [ Upstream commit ee6581ceba7f8314b81b2f2a81f1cf3f67c679e2 ] Incremental patch to fix the unchecked dereference in acpi_nfit_ctl. Reported by Dan Carpenter: "acpi/nfit: fix cmd_rc for acpi_nfit_ctl to always return a value" from Jun 28, 2018, leads to the following Smatch complaint: drivers/acpi/nfit/core.c:578 acpi_nfit_ctl() warn: variable dereferenced before check 'cmd_rc' (see line 411) drivers/acpi/nfit/core.c 410 411 *cmd_rc = -EINVAL; ^^^^^^^^^^^^^^^^^^ Patch adds unchecked dereference. Fixes: c1985cefd844 ("acpi/nfit: fix cmd_rc for acpi_nfit_ctl to always return a value") Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/nfit/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -224,7 +224,8 @@ int acpi_nfit_ctl(struct nvdimm_bus_desc const guid_t *guid; int rc, i; - *cmd_rc = -EINVAL; + if (cmd_rc) + *cmd_rc = -EINVAL; func = cmd; if (cmd == ND_CMD_CALL) { call_pkg = buf; @@ -315,7 +316,8 @@ int acpi_nfit_ctl(struct nvdimm_bus_desc * If we return an error (like elsewhere) then caller wouldn't * be able to rely upon data returned to make calculation. */ - *cmd_rc = 0; + if (cmd_rc) + *cmd_rc = 0; return 0; }