Hi Phil, On Tue, Jun 07, 2022 at 04:35:32PM +0100, Phil Elwell wrote: > Jason, > > On 07/06/2022 16:14, Jason A. Donenfeld wrote: > > Hey again, > > > > On Tue, Jun 07, 2022 at 10:15:27AM +0100, Phil Elwell wrote: > >> On 07/06/2022 09:43, Jason A. Donenfeld wrote: > >>> Hi Phil, > >>> > >>> On Tue, Jun 7, 2022 at 10:29 AM Phil Elwell <phil@xxxxxxxxxxxxxxx> wrote: > >>>> > >>>> This patch is fatal for me in the downstream Raspberry Pi kernel - it locks up > >>>> on boot even before the earlycon output is available. Hacking jump_label_init to > >>>> skip the jump_entry for "crng_is_ready" allows it to boot, but is likely to have > >>>> consequences further down the line. > >>> > >>> Also, reading this a few times, I'm not 100% sure I understand what > >>> you did to hack around this and why that works. Think you could paste > >>> your hackpatch just out of interest to the discussion (but obviously > >>> not to be applied)? > >> > >> This is the minimal version of my workaround patch that at least allows the > >> board to boot. Bear in mind that it was written with no previous knowledge of > >> jump labels and was arrived at by iteratively bisecting the list of jump_labels > >> until the first dangerous one was found, then later working out that there was > >> only one. > > > > Looks like this patch fails due to CONFIG_STRICT_KERNEL_RWX. > > Investigating deeper now, but that for starters seems to be the > > differentiating factor between my prior test rig and one that reproduces > > the error. I assume your raspi also sets CONFIG_STRICT_KERNEL_RWX. > > Yes, it does, as does multi_v7_defconfig. Oh good. Adjusting my CI now to have that. Having tickled arch/arm/ a little bit now, this is looking sort of complicated. So I think I might be leaning toward giving up and just rolling with <https://git.zx2c4.com/linux-rng/commit/?id=78f79dda>. Unless of course somebody has some ARM chops and can think of a quick easy fix. Jason
