On Mon, Oct 24, 2016 at 05:26:37PM +0200, Arnd Bergmann wrote:
> The intialization function checks for various failure scenarios, but
> unfortunately the compiler gets a little confused about the possible
> combinations, leading to a false-positive build warning when
> -Wmaybe-uninitialized is set:
>
> arch/x86/events/core.c: In function ‘init_hw_perf_events’:
> arch/x86/events/core.c:264:3: warning: ‘reg_fail’ may be used uninitialized
> in this function [-Wmaybe-uninitialized]
> arch/x86/events/core.c:264:3: warning: ‘val_fail’ may be used uninitialized
> in this function [-Wmaybe-uninitialized]
> pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n",
>
> It seems reasonable to move the check for the broken BIOS a little
> higher in the function, which will lead to the kernel warning about
> both the BIOS and and broken hardware if both are faulty, but it
> has no effect otherwise at runtime.
>
> Moving it ahead of the check for broken hardware however gets rid
> of the compile-time warning.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
Wouldn't something simple like this not be, well, simpler?
---
arch/x86/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index d31735f37ed7..3bc4d76ce0bb 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -190,8 +190,8 @@ static void release_pmc_hardware(void) {}
static bool check_hw_exists(void)
{
- u64 val, val_fail, val_new= ~0;
- int i, reg, reg_fail, ret = 0;
+ u64 val, val_fail = 0, val_new= ~0;
+ int i, reg, reg_fail = 0, ret = 0;
int bios_fail = 0;
int reg_safe = -1;
