Re: [Qemu-devel] qemu-arm fails on test-mmap

[Martin Mohring]

Hi,

yesterday, we tracked down the problem to a kernel bug in this area:
http://bugzilla.kernel.org/attachment.cgi?id=17219 What do I want to say
with this: the user mode memory allocator does not work because it runs
into a kernel bug.

Kudos to Jan-Simon. Has anyone an idea how to handle such a case....
Patching the kernel is not the best idea. We will check which kernels
are affected.

Cheers, Martin

Jan-Simon Möller wrote:
> A quick hack around is this:
>
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index e05caa0..a04d6b1 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -316,8 +316,14 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
>          if (addr == addr_start)
>              return (abi_ulong)-1;
>      }
> -    if (start == 0)
> -        mmap_next_start = addr + size;
> +    if (start == 0) {
> +        abi_ulong mynext = addr + size ;
> +        if ( (mynext > 0x5f000000) && (mynext < 0x65000000) ) {
> +          mmap_next_start = 0x65000000 ;
> +        } else {
> +          mmap_next_start = addr + size;
> +        }
> +    }
>      return addr;
>  }
>
>
> But this is for sure not the real solution.
>
> Best,
> Jan-Simon
>
>
>