On Mon, 27 Feb 2023 at 18:17, Linux regression tracking (Thorsten Leemhuis) <regressions@xxxxxxxxxxxxx> wrote: > > > > On 27.02.23 17:14, Ard Biesheuvel wrote: > > On Mon, 27 Feb 2023 at 16:08, Linux regression tracking (Thorsten > > Leemhuis) <regressions@xxxxxxxxxxxxx> wrote: > >> > >> [CCing the regression list, as it should be in the loop for regressions: > >> https://docs.kernel.org/admin-guide/reporting-regressions.html] > >> > >> On 07.02.23 12:29, Will Deacon wrote: > >>> On Tue, Jan 31, 2023 at 05:03:32PM +0100, Ard Biesheuvel wrote: > >>>> On Tue, 31 Jan 2023 at 16:07, Will Deacon <will@xxxxxxxxxx> wrote: > >>>>> On Tue, Jan 31, 2023 at 03:06:44PM +0000, Will Deacon wrote: > >>>>>> 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: > >>>>>>>> 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. > >>> > >>> That sounds like a good idea to me. > >>> > >>> Liu Shixin -- do you think you could have a go at implementing Ard's > >>> suggestion instead? > >> > >> Liu Shixin, did you ever look into realizing this idea? > >> > >> Or was some progress already made and I just missed it? > > > > This patch > > > > https://lore.kernel.org/all/20230223204101.1500373-1-ardb@xxxxxxxxxx/ > > > > should fix the issue. > > Great, many thx. > > >> I'm asking, as the idea discussed afaics is not only supposed to fix the > >> regression you tried to address, but also one that is now three months > >> old and stalled since Mid-December -- which is really unfortunate, as > >> that's not how regressions should be handled. :-/ > > > > Is it documented anywhere how regressions should be handled? > > https://docs.kernel.org/process/handling-regressions.html > > Side note: that also mentions use of the "Link" tag. If the patch had > one, I'd noticed it and wouldn't bothered anyone here. > Thanks for the reference. I wasn't aware that that document existed. However, please be careful with calling everything a regression: in this particular case, the 10G pmem device simply never worked in this configuration, and so calling this a regression, and quoting all these rules that we must now abide by is, quite frankly, not entirely appropriate. Can we please reserve the 'regression' label for cases where the workflow of a real user stopped working after a kernel change? I agree that this must never happen, and so we should prioritize those cases over the ones that are just ordinary bugs and not regressions. > > The > > mailing list is flooded with hard to reproduce reports from users as > > well as automatic fuzzers and build bots, so I don't think it is > > entirely unreasonable to move unresponsive reporters to the back of > > the queue. > > I do that sometimes, but fwiw, from what I can see it wasn't a reporter > that was unresponsive: > > https://lore.kernel.org/linux-arm-kernel/c1ff5cae-7f56-7fdb-c832-ffbcc177535b@xxxxxxxxxxxxx/ > > But I might be missing something, sorry if I do. And there was the > festive season what complicated everything. Whatever, as long as this > this is fixed. > > /me wonders if we should ask "chenxiang (M)" to test that patch, too; > but /me is not even totally sure it's the same problem > Yes, to me it looks like exactly the same issue. > >> But well, it afaik was > >> caused by a patch from Ard, so it's obviously not your job to address > >> it. But it seems you were working on it. > > > > We are all working together here, so please refrain from telling > > people what they should or should not be working on. (I am aware that > > you probably did not mean it that way, but things tend to get lost in > > translation very easily on the mailing list) > > Maybe I found the wrong words, sorry. > No worries. Your work is much appreciated, as I am sure it's a thankless job at times. Thanks, Ard.
