• Arnd Bergmann's avatar
    ACPI / power: Avoid maybe-uninitialized warning · ec042914
    Arnd Bergmann authored
    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>
    [bwh: Backported to 3.2: adjust context]
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    ec042914
power.c 16.1 KB