[PATCH RFC] arm64/vmalloc: use module region only for module_alloc() if CONFIG_RANDOMIZE_BASE is set

[Will Deacon]

+Ard -- full thread here:

https://lore.kernel.org/all/20221227092634.445212-1-liushixin2@huawei.com/

On Sun, Jan 29, 2023 at 01:41:47PM -0800, Andrew Morton wrote:
> On Sun, 29 Jan 2023 10:44:31 +0800 Liu Shixin <liushixin2 at huawei.com> wrote:
> 
> > Hi,
> > 
> > 
> > This patch seems to have been lost in the corner. Recently I've meet this problem again
> > 
> > on v6.1, so I would like to propose this patch again.
> > 
> > 
> > Thanks,
> > 
> > 
> > On 2022/12/27 17:26, Liu Shixin wrote:
> > > After I add a 10GB pmem device, I got the following error message when
> > > insert module:
> > >
> > >  insmod: vmalloc error: size 16384, vm_struct allocation failed,
> > >  mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0
> > >
> > > If CONFIG_RANDOMIZE_BASE is set, the module region can be located in the
> > > vmalloc region entirely. Although module_alloc() can fall back to a 2GB
> > > window if ARM64_MODULE_PLTS is set, the module region is still easily
> > > exhausted because the module region is located at bottom of vmalloc region
> > > and the vmalloc region is allocated from bottom to top.
> > >
> > > Skip module region if not calling from module_alloc().
> > >
> 
> I'll assume this is for the arm tree.
> 
> Acked-by: Andrew Morton <akpm at linux-foundation.org>

This looks like the same issue previously reported at:

https://lore.kernel.org/all/e6a804de-a5f7-c551-ffba-e09d04e438fc@hisilicon.com/

where Ard had a few suggestions but, afaict, they didn't help.

Will