[PATCH V9 20/20] riscv: compat: Add COMPAT Kbuild skeletal support

[Heiko Stübner]

Am Mittwoch, 25. Mai 2022, 18:08:22 CEST schrieb Guo Ren:
> Thx Heiko & Guenter,
> 
> On Wed, May 25, 2022 at 7:10 PM Heiko Stübner <heiko at sntech.de> wrote:
> >
> > Am Mittwoch, 25. Mai 2022, 12:57:30 CEST schrieb Heiko Stübner:
> > > Am Mittwoch, 25. Mai 2022, 00:06:46 CEST schrieb Guenter Roeck:
> > > > On Wed, May 25, 2022 at 01:46:38AM +0800, Guo Ren wrote:
> > > > [ ... ]
> > > >
> > > > > > The problem is come from "__dls3's vdso decode part in musl's
> > > > > > ldso/dynlink.c". The ehdr->e_phnum & ehdr->e_phentsize are wrong.
> > > > > >
> > > > > > I think the root cause is from musl's implementation with the wrong
> > > > > > elf parser. I would fix that soon.
> > > > > Not elf parser, it's "aux vector just past environ[]". I think I could
> > > > > solve this, but anyone who could help dig in is welcome.
> > > > >
> > > >
> > > > I am not sure I understand what you are saying here. Point is that my
> > > > root file system, generated with musl a year or so ago, crashes with
> > > > your patch set applied. That is a regression, even if there is a bug
> > > > in musl.
> Thx for the report, it's a valuable regression for riscv-compat.
> 
> > >
> > > Also as I said in the other part of the thread, the rootfs seems innocent,
> > > as my completely-standard Debian riscv64 rootfs is also affected.
> > >
> > > The merged version seems to be v12 [0] - not sure how we this discussion
> > > ended up in v9, but I just tested this revision in two variants:
> > >
> > > - v5.17 + this v9 -> works nicely
> >
> > I take that back ... now going back to that build I somehow also run into
> > that issue here ... will investigate more.
> Yeah, it's my fault. I've fixed up it, please have a try:
> 
> https://lore.kernel.org/linux-riscv/20220525160404.2930984-1-guoren@kernel.org/T/#u

very cool that you found the issue.
I've tested your patch and it seems to fix the issue for me.

Thanks for figuring out the cause
Heiko


> > > - v5.18-rc6 + this v9 (rebased onto it) -> breaks the boot
> > >   The only rebase-conflict was with the introduction of restartable
> > >   sequences and removal of the tracehook include, but turning CONFIG_RSEQ
> > >   off doesn't seem to affect the breakage.
> > >
> > > So it looks like something changed between 5.17 and 5.18 that causes the issue.
> > >
> > >
> > > Heiko
> > >
> > >
> > > [0] https://lore.kernel.org/all/20220405071314.3225832-1-guoren@kernel.org/
> > >
> >
> >
> >
> >
> 
> 
>