On 6/6/19 1:09 PM, Yu-cheng Yu wrote: > + modify_fpu_regs_begin(); > + rdmsrl(MSR_IA32_U_CET, r); > + r |= (MSR_IA32_CET_LEG_IW_EN | bitmap); > + wrmsrl(MSR_IA32_U_CET, r); > + modify_fpu_regs_end(); Isn't there a bunch of other stuff in this MSR? It seems like the bitmap value would allow overwriting lots of bits in the MSR that have nothing to do with the bitmap... in a prctl() that's supposed to only be dealing with the bitmap.