| From fe8c470ab87d90e4b5115902dd94eced7e3305c3 Mon Sep 17 00:00:00 2001 |
| From: Arnd Bergmann <arnd@arndb.de> |
| Date: Wed, 19 Apr 2017 19:47:04 +0200 |
| Subject: ACPI / power: Avoid maybe-uninitialized warning |
| |
| From: Arnd Bergmann <arnd@arndb.de> |
| |
| commit fe8c470ab87d90e4b5115902dd94eced7e3305c3 upstream. |
| |
| gcc -O2 cannot always prove that the loop in acpi_power_get_inferred_state() |
| is enterered at least once, so it assumes that cur_state might not get |
| initialized: |
| |
| drivers/acpi/power.c: In function 'acpi_power_get_inferred_state': |
| drivers/acpi/power.c:222:9: error: 'cur_state' may be used uninitialized in this function [-Werror=maybe-uninitialized] |
| |
| This sets the variable to zero at the start of the loop, to ensure that |
| there is well-defined behavior even for an empty list. This gets rid of |
| the warning. |
| |
| The warning first showed up when the -Os flag got removed in a bug fix |
| patch in linux-4.11-rc5. |
| |
| I would suggest merging this addon patch on top of that bug fix to avoid |
| introducing a new warning in the stable kernels. |
| |
| Fixes: 61b79e16c68d (ACPI: Fix incompatibility with mcount-based function graph tracing) |
| Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/acpi/power.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/drivers/acpi/power.c |
| +++ b/drivers/acpi/power.c |
| @@ -200,6 +200,7 @@ static int acpi_power_get_list_state(str |
| return -EINVAL; |
| |
| /* The state of the list is 'on' IFF all resources are 'on'. */ |
| + cur_state = 0; |
| list_for_each_entry(entry, list, node) { |
| struct acpi_power_resource *resource = entry->resource; |
| acpi_handle handle = resource->device.handle; |
