Re: [Qemu-devel] linux-user mmap bug

[Richard Henderson]

On 05/21/2010 06:28 AM, Edgar E. Iglesias wrote:
>          ptr = mmap(g2h(addr), size, PROT_NONE,
> -                   MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
> +                   /* When the kernel returns addresses that the guest
> +                      cannot use we might need to fallback to fixed
> +                      allocations.  */
> +                   (addr ? MAP_FIXED : 0)
> +                   | MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);

NACK.  We are in fact probing for a free address in this loop,
so you don't know that the address being tested is in fact free.

I have a patch series that attempts to clean this up, but it 
isn't quite optimal.  I'll post it for reference, however.


r~