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

[Richard Henderson]

On 1/29/24 05:26, Ilya Leoshkevich wrote:
> 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.

Can you think of a failure mode?  I couldn't.
That's why I added the assert.

I suppose there's the always present threat of running out of vmas...


r~