STM32L05 interrupt problem

[hamdi.tn]

Hi,

So am using PC13 PC14 and PC15 as switch input configured with falling interrupt , the bizarre thing is when i only set one of them as interrupt input it work, when i set 2 or more it stuck in the interrupt routine,
I checked with the debugger that if for example PC15 and PC14 are in interrupt configuration EXTI 14 flag is always set, if PC15 and PC14 and PC13 are configured , EXTI14 and 13 flag are always set, made me insane 
it happen that PC14 and PC15 are also OSC-IN but the ds said that they can be used as a simple I/O as well, the proof they work individually but not all of them .. am lost , Help 

[hamdi.tn]

Solved
For those who may get stuck on this too , for a reason i don't understand the HAL library is not writing the SYSCFG_EXTI register, i configured the interrupt with direct addressing not with library functions  ... it work now