Re: [PATCH] linux-user: mremap fails with EFAULT if address range overlaps with stack guard

[Laurent Vivier]

Le 05/03/2020 à 22:05, Tobias Koch a écrit :
> If the address range starting at old_address overlaps with the stack guard it
> is invalid and mremap must fail with EFAULT. The musl c library relies on this
> behavior to detect the stack size, which it does by doing consecutive mremaps
> until it hits the stack guard. Without this patch, software (such as the Ruby
> interpreter) that calls pthread_getattr_np under musl will crash on 32 bit
> targets emulated on a 64 bit host.

Could you share some pointers to the code that is doing this?

We have already this kind of code in linux-user/elfload.c,
setup_arg_pages(): could you check why it doesn't work?

Thanks,
Laurent