On 09/04/14 15:21, Jan Beulich wrote: >>>> On 09.04.14 at 16:06, <boris.ostrov...@oracle.com> wrote: >> --- a/arch/x86/xen/xen-asm_32.S >> +++ b/arch/x86/xen/xen-asm_32.S >> @@ -88,7 +88,11 @@ ENTRY(xen_iret) >> * avoid having to reload %fs >> */ >> #ifdef CONFIG_SMP >> + pushw %fs >> + movl $(__KERNEL_PERCPU), %eax >> + movl %eax, %fs >> GET_THREAD_INFO(%eax) >> + popw %fs > > I don't think it's guaranteed that this can't fault.
If loading %fs faults when it is restored previously, the fixup zeros the value. However, this later load could still fault even if the first succeeded. Suggest copying the fixup section from the RESTORE_REGS macros in arch/x86/kernel/entry_32.S David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
