Is this a kernel BUG? ///Re: [Question] Can we use SIGRTMIN when vdso disabled on X86?

Leizhen (ThunderTown)
2018-06-06T07:53:21Z

On 2018/6/5 19:24, Leizhen (ThunderTown) wrote:
> After I executed "echo 0 > /proc/sys/abi/vsyscall32" to disable vdso, the rt_sigaction01 test case from ltp_2015 failed.
> The test case source code please refer to the attachment, and the output as blow:
>
> -----------------
> ./rt_sigaction01
> rt_sigaction01 0 TINFO : signal: 34
> rt_sigaction01 1 TPASS : rt_sigaction call succeeded: result = 0
> rt_sigaction01 0 TINFO : sa.sa_flags = SA_RESETHAND|SA_SIGINFO
> rt_sigaction01 0 TINFO : Signal Handler Called with signal number 34
>
> Segmentation fault
> ------------------
>
>
> Is this the desired result? In function ia32_setup_rt_frame, I found below code:
>
> if (ksig->ka.sa.sa_flags & SA_RESTORER)
> restorer = ksig->ka.sa.sa_restorer;
> else
> restorer = current->mm->context.vdso +
> vdso_image_32.sym___kernel_rt_sigreturn;
> put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
>
> Because the vdso is disabled, so current->mm->context.vdso is NULL, which cause the result of frame->pretcode invalid.
>
> I'm not sure whether this is a kernel bug or just an error of test case itself. Can anyone help me?
>

--
Thanks!
BestRegards