On 2023/2/1 0:03, Ard Biesheuvel wrote: > On Tue, 31 Jan 2023 at 16:07, Will Deacon <will@xxxxxxxxxx> wrote: >> Now really adding Ard... >> >> On Tue, Jan 31, 2023 at 03:06:44PM +0000, Will Deacon wrote: >>> +Ard -- full thread here: >>> >>> https://lore.kernel.org/all/20221227092634.445212-1-liushixin2@xxxxxxxxxx/ >>> >>> 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@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx> >>> This looks like the same issue previously reported at: >>> >>> https://lore.kernel.org/all/e6a804de-a5f7-c551-ffba-e09d04e438fc@xxxxxxxxxxxxx/ >>> >>> where Ard had a few suggestions but, afaict, they didn't help. >>> > Thanks for the cc. > > So this is a bit clunky, and I wonder whether we wouldn't be better > off just splitting the vmalloc region into two separate regions: one > for the kernel and modules, and one for everything else. That way, we > lose one bit of entropy in the randomized placement, but the default > 48-bit VA space is vast anway, and even on 39-bit VA configs (such as > Android), I seriously doubt that we come anywhere close to exhausting > the vmalloc space today. > . Thanks for your advice. >
