Commit 4420e5f3 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Greg Kroah-Hartman

ACPI / power: Avoid maybe-uninitialized warning

commit fe8c470a 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: 61b79e16 (ACPI: Fix incompatibility with mcount-based function graph tracing)
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 11ba522d
......@@ -200,6 +200,7 @@ static int acpi_power_get_list_state(struct list_head *list, int *state)
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;
......
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