Re: [PATCH v3 22/33] linux-user: Split out mmap_h_lt_g

[Ilya Leoshkevich]

On Tue, Jan 02, 2024 at 12:57:57PM +1100, Richard Henderson wrote:
> Work much harder to get alignment and mapping beyond the end
> of the file correct.  Both of which are excercised by our
> test-mmap for alpha (8k pages) on any 4k page host.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/mmap.c | 156 +++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 125 insertions(+), 31 deletions(-)

[...]

> +        if (fileend_adj) {
> +            void *t = mmap(p, len - fileend_adj, host_prot,
> +                           (flags & ~MAP_FIXED_NOREPLACE) | MAP_FIXED,
> +                           fd, offset);
> +            assert(t != MAP_FAILED);

Is it possible to recover here? Of course, we are remapping the memory
we've mapped a few lines earlier, but asserting the syscall result
looks a bit odd.

[...]

> +        if (!(flags & MAP_ANONYMOUS)) {
> +            void *t = mmap(p, len - fileend_adj, host_prot,
> +                           flags | MAP_FIXED, fd, offset);
> +            assert(t != MAP_FAILED);

Same here.