[Crash-utility] Re: bt -f fix for s390(x)

[Dave Anderson]

Michael Holzheu wrote:

> Hi Dave,
>
> Here comes a fix for the bt -f command.
>
> The problem is that when the backchain is invalid on s390(x) we can get huge values for the stackframe size. This can lead to a termination of crash with a SIGSEGV. To fix this, we have to use in case of an invalid backchain the difference between the current backchain and the end of the stack as stackframe size.
>
> ---
>

Thanks Michael -- queued for the next release.

Dave


>
> diff -Naur crash-4.0-2.31/s390.c crash-4.0-2.31-s390-bt-f.fix/s390.c
> --- crash-4.0-2.31/s390.c       2006-06-27 16:15:32.000000000 +0200
> +++ crash-4.0-2.31-s390-bt-f.fix/s390.c 2006-07-03 16:37:34.000000000 +0200
> @@ -714,7 +714,9 @@
>                                 frame_size = stack_base - old_backchain
>                                              + KERNEL_STACK_SIZE;
>                         } else {
> -                               frame_size = backchain - old_backchain;
> +                               frame_size = MIN((backchain - old_backchain),
> +                                       (stack_base - old_backchain +
> +                                       KERNEL_STACK_SIZE));
>                         }
>                         for(j=0; j< frame_size; j+=4){
>                                 if(j % 16 == 0){
> diff -Naur crash-4.0-2.31/s390x.c crash-4.0-2.31-s390-bt-f.fix/s390x.c
> --- crash-4.0-2.31/s390x.c      2006-06-27 16:15:32.000000000 +0200
> +++ crash-4.0-2.31-s390-bt-f.fix/s390x.c        2006-07-03 16:37:37.000000000 +0200
> @@ -747,7 +747,9 @@
>                                 frame_size = stack_base - old_backchain
>                                              + KERNEL_STACK_SIZE;
>                         } else {
> -                               frame_size = backchain - old_backchain;
> +                               frame_size = MIN((backchain - old_backchain),
> +                                       (stack_base - old_backchain +
> +                                       KERNEL_STACK_SIZE));
>                         }
>                         for(j=0; j< frame_size; j+=4){
>                                 if(j % 16 == 0){