Re: [Qemu-trivial] [Qemu-devel] [PATCH] coroutine-sigaltstack: Change jmp_buf to sigjmp_buf

[Peter Maydell]

On 8 November 2014 03:51, Willem Pinckaers <address@hidden> wrote:
> This is a simple patch to change the type of old_env from jmp_buf
> to sigjmp_buf.  old_env is used by sigsetjmp and as such should be
> a sigjmp_buf.
>
> This fixes a stack_chk fail in a OSX 32bit build. Since at least on
> OSX sigjmp_buf is four bytes larger then a jmpbuf, resulting in an
> overflow in sigsetjmp. Due to variable reordering this overwrites
> the stack cookie.
>
> Signed-off-by: Willem Pinckaers <address@hidden>
> ---
>  coroutine-sigaltstack.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/coroutine-sigaltstack.c b/coroutine-sigaltstack.c
> index 3de0bb3..63519ff 100644
> --- a/coroutine-sigaltstack.c
> +++ b/coroutine-sigaltstack.c
> @@ -155,7 +155,7 @@ Coroutine *qemu_coroutine_new(void)
>      stack_t oss;
>      sigset_t sigs;
>      sigset_t osigs;
> -    jmp_buf old_env;
> +    sigjmp_buf old_env;
>
>      /* The way to manipulate stack is with the sigaltstack function. We
>       * prepare a stack, with it delivering a signal to ourselves and then

Reviewed-by: Peter Maydell <address@hidden>

I think I must have missed this one when I converted all the jmp_buf
to sigjmp_buf in commit 6ab7e546.

-- PMM