ACPI / power: Avoid maybe-uninitialized warning
authorArnd Bergmann <arnd@arndb.de>
Wed, 19 Apr 2017 17:47:04 +0000 (19:47 +0200)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 19 Apr 2017 20:46:10 +0000 (22:46 +0200)
commitfe8c470ab87d90e4b5115902dd94eced7e3305c3
tree66dd1159e145c38735959362ceb63f9907649ab4
parent4f7d029b9bf009fbee76bb10c0c4351a1870d2f3
ACPI / power: Avoid maybe-uninitialized warning

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)
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/acpi/power.c