Re: [PATCH v1 4/7] linux-user: more debug for init_guest_space

[Laurent Vivier <laurent@vivier.eu>]

Le 27/03/2020 à 10:49, Alex Bennée a écrit :
> Searching for memory space can cause problems so lets extend the
> CPU_LOG_PAGE output so you can watch init_guest_space fail to
> allocate memory. A more involved fix is actually required to make this
> function play nicely with the large guard pages the sanitiser likes to
> use.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  linux-user/elfload.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 8198be04460..619c054cc48 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -2172,6 +2172,8 @@ unsigned long init_guest_space(unsigned long host_start,
>  
>          /* Check to see if the address is valid.  */
>          if (host_start && real_start != current_start) {
> +            qemu_log_mask(CPU_LOG_PAGE, "invalid %lx && %lx != %lx\n",
> +                          host_start, real_start, current_start);
>              goto try_again;
>          }
>  
> @@ -2240,7 +2242,11 @@ unsigned long init_guest_space(unsigned long host_start,
>           * probably a bad strategy if not, which means we got here
>           * because of trouble with ARM commpage setup.
>           */
> -        munmap((void *)real_start, real_size);
> +        if (munmap((void *)real_start, real_size) != 0) {
> +            error_report("%s: failed to unmap %lx:%lx (%s)", __func__,
> +                         real_start, real_size, strerror(errno));
> +            abort();
> +        }
>          current_start += align;
>          if (host_start == current_start) {
>              /* Theoretically possible if host doesn't have any suitably
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>