Re: Error on loading some network Kernel modules

From: Anup Patel <anup@brainfault.org>
To: Aurelien Jarno <aurelien@aurel32.net>
Cc: Carlos Eduardo de Paula <me@carlosedp.com>,
	David Abdurachmanov <david.abdurachmanov@gmail.com>,
	Paul Walmsley <paul@pwsan.com>,
	Vincent Chen <vincent.chen@sifive.com>,
	Romain Dolbeau <romain.dolbeau@european-processor-initiative.eu>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: Error on loading some network Kernel modules
Date: Sat, 1 Feb 2020 13:22:22 +0530	[thread overview]
Message-ID: <CAAhSdy03C==7PmuXE441BtDJH8H07rOH-u+-_sZJG70tbTrJcA@mail.gmail.com> (raw)
In-Reply-To: <20200131201118.GA4121429@aurel32.net>

On Sat, Feb 1, 2020 at 1:41 AM Aurelien Jarno <aurelien@aurel32.net> wrote:
>
> On 2020-01-30 17:20, David Abdurachmanov wrote:
> > On Thu, Jan 30, 2020 at 4:00 AM Paul Walmsley <paul@pwsan.com> wrote:
> > >
> > > On Tue, 28 Jan 2020, Carlos Eduardo de Paula wrote:
> > >
> > > > I currently run stock Kernel 5.5.0-rc7 on my Unleashed board with most
> > > > network features I need baked into the kernel instead of modules.
> > > >
> > > > I tried building a kernel with these network features as modules but
> > > > when loading some of them I got this error:
> > > >
> > > > root@unleashed:~# uname -a
> > > > Linux unleashed 5.5.0-rc7-dirty #4 SMP Fri Jan 24 18:16:43 -02 2020
> > > > riscv64 GNU/Linux
> > > >
> > > > root@unleashed:~# modprobe br_netfilter
> > > > [  139.290533] br_netfilter: target ffffffe0000422d8 can not be
> > > > addressed by the 32-bit offset from PC = 000000003dfd6deb
> > >
> > > This is a known issue:
> > >
> > > https://lore.kernel.org/linux-riscv/1572281840733.3517@european-processor-initiative.eu/
> > >
> > > https://lore.kernel.org/linux-riscv/20191029105055.GA20736@aurel32.net/#r
> > >
> > > Vincent is looking into it and I expect there will be a fix soon.
> > >
> >
> > Is this patch solving the problem?
> >
> > https://github.com/bjoto/linux/commit/8a56d1c8e8e91c1bc3893946d52b9217c96e1589
>
> I have just tried that patch on top of a 5.4.13 kernel, and I confirm it
> fixes the issue. Thanks!

I guess this patch was lost over time.

First of all we need to rebase this patch on latest kernel.

The MODULES_xyz defines are totally redundant and create
confusion because with these defines it seems we are creating
separate virtual memory region for modules which is not true.
In fact, the patch only tries to ensure that modules are allocated
from the end-of VMALLOC region.

I suggest to drop all MODULES_xyz defines and implement
module_alloc() as follows:

void *module_alloc(unsigned long size)
{
return __vmalloc_node_range(size, 1, VMALLOC_END - SZ_128M,
VMALLOC_END, GFP_KERNEL,
PAGE_KERNEL_EXEC, 0,
NUMA_NO_NODE,
__builtin_return_address(0));
}

Maybe we can even have a kconfig options for MODULES_SIZE
which can be used in-place of SZ_128M in above code.

Should I send a patch on latest kernel ??

Regards,
Anup