[PATCH v11 00/69] Introducing the Maple Tree

[Liam Howlett]

* Liam R. Howlett <Liam.Howlett at Oracle.com> [220717 08:42]:
> * Yu Zhao <yuzhao at google.com> [220717 01:58]:
> > On Sat, Jul 16, 2022 at 10:20 PM Andrew Morton
> > <akpm at linux-foundation.org> wrote:
> > >
> > > On Sun, 17 Jul 2022 02:46:32 +0000 Liam Howlett <liam.howlett at oracle.com> wrote:
> > ...
> > >         gap = mas.index;
> > >         gap += (info->align_offset - gap) & info->align_mask;
> > > -       VM_BUG_ON(gap + info->length > info->high_limit);
> > > -       VM_BUG_ON(gap + info->length > mas.last);
> 
> What arch did you hit these on?  David asked for me to restore some of
> the BUG_ONs in these functions and I guess I got it wrong.

I think these should be removed until I better test them.

> 
> > 
> > These VM_BUG_ONs are new, and I hit the second one quickly:
> > 
> >   kernel BUG at mm/mmap.c:1631!
> >   RIP: 0010:vm_unmapped_area+0xdb/0x1c0
> >   Call Trace:
> >    <TASK>
> >    arch_get_unmapped_area+0x1ee/0x220
> >    arch_get_unmapped_area_topdown+0x25a/0x290
> >    get_unmapped_area+0x92/0x100
> >    do_mmap+0x13f/0x560
> >    vm_mmap_pgoff+0xcd/0x170