Re: [Qemu-arm] [PATCH for-2.12] linux-user/signal.c: Ensure AArch64 signal frame isn't too small

[Peter Maydell]

On 9 April 2018 at 23:05, Richard Henderson <address@hidden> wrote:
> On 04/10/2018 12:07 AM, Peter Maydell wrote:
>> In particular the dash shell
>> would segfault if the frame wasn't as big enough.
>
> Ah, that was the critical difference in my failure to replicate -- the fedora
> sysroot doesn't have dash.  As you say, the patch matches the kernel so,
>
> Reviewed-by: Richard Henderson <address@hidden>
>
> That said, what the hell is dash doing that relies on this?

Yeah, I want to look more closely at what's going on here
tomorrow -- this is definitely a bug fix but I'm wondering
if it only masks a different underlying issue.

The spurious SEGV is the result of the call to
lock_user_struct() in target_setup_frame() failing
if we use too small a frame size, resulting in our
calling force_sigsegv().

thanks
-- PMM