When __acpi_match_device() is called it would be possible to have ACPI ID table a MULL pointer. To avoid potential dereference, check for this before traverse. While here, remove redundant 'else'. Fixes: 80212a162329 ("ACPI / bus: Introduce acpi_get_match_data() function") Cc: Sinan Kaya <okaya@xxxxxxxxxxxxxx> Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> Cc: Vinod Koul <vinod.koul@xxxxxxxxx> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> --- v2: new patch drivers/acpi/bus.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index a87a97bf75f8..f3a7c29e9190 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -745,11 +745,13 @@ static const struct acpi_device_id *__acpi_match_device( list_for_each_entry(hwid, &device->pnp.ids, list) { /* First, check the ACPI/PNP IDs provided by the caller. */ - for (id = ids; id->id[0] || id->cls; id++) { - if (id->id[0] && !strcmp((char *) id->id, hwid->id)) - return id; - else if (id->cls && __acpi_match_device_cls(id, hwid)) - return id; + if (ids) { + for (id = ids; id->id[0] || id->cls; id++) { + if (id->id[0] && !strcmp((char *)id->id, hwid->id)) + return id; + if (id->cls && __acpi_match_device_cls(id, hwid)) + return id; + } } /* -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html