From: Finn Thain <fthain@linux-m68k•org>
To: Sasha Levin <sashal@kernel•org>
Cc: Peter Zijlstra <peterz@infradead•org>,
Ard Biesheuvel <ardb@kernel•org>,
Andrew Morton <akpm@linux-foundation•org>,
Will Deacon <will@kernel•org>, Arnd Bergmann <arnd@arndb•de>,
Stephen Rothwell <sfr@canb•auug.org.au>,
x86@kernel•org,
Linux Kernel Mailing List <linux-kernel@vger•kernel.org>,
Linux Next Mailing List <linux-next@vger•kernel.org>
Subject: Re: linux-next: build failure after merge of the mm-nonmm-unstable tree
Date: Mon, 29 Dec 2025 19:56:44 +1100 (AEDT) [thread overview]
Message-ID: <df9fbd22-a648-ada4-fee0-68fe4325ff82@linux-m68k.org> (raw)
In-Reply-To: <aU67sD1u83Qrpvdu@laps>
On Fri, 26 Dec 2025, Sasha Levin wrote:
> On Sun, Dec 21, 2025 at 01:58:17PM +1100, Finn Thain wrote:
> >
> >On Thu, 18 Dec 2025, Stephen Rothwell wrote:
> >
> >> After merging the mm-nonmm-unstable tree, today's linux-next build
> >> (x86_64 allmodconfig) failed like this:
> >>
> >> x86_64-linux-gnu-ld: error: unplaced orphan section `__bug_table' from
> >> `arch/x86/boot/compressed/sev-handle-vc.o'
> >>
> >
> >I found that I could reproduce the same build failure after applying
> >Peter's patch to v6.19-rc1. So it's not confined to linux-next. I used
> >allnoconfig with CONFIG_LD_ORPHAN_WARN_LEVEL=error and
> >CONFIG_AMD_MEM_ENCRYPT=y because allmodconfig takes forever to build.
> >
> >The patch in question is this one:
> >https://lore.kernel.org/lkml/0c18fd08ef19497768070783da28086e01d11a00.1765866665.git.fthain@linux-m68k.org/
> >
> >I may have found a solution for the problem, but I don't understand this
> >code, so I've Cc'd Ard et al. I don't know whether the __bug_table section
> >is relevant to sev-handle-vc.c. If that section is not desired, I propose
> >to make this change to Peter's patch --
>
> I think that the issue here is that we're trying to use WARN in the
> early boot context. We should probably add CONFIG_DEBUG_ATOMIC to the
> list of configs we disable for that:
>
> diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
> index 4f86c5903e03..bb36dcef7d08 100644
> --- a/arch/x86/boot/compressed/misc.h
> +++ b/arch/x86/boot/compressed/misc.h
> @@ -14,6 +14,7 @@
> #undef CONFIG_ARCH_HAS_LAZY_MMU_MODE
> #undef CONFIG_KASAN
> #undef CONFIG_KASAN_GENERIC
> +#undef CONFIG_DEBUG_ATOMIC
>
Thanks for sending that suggestion. It does fix the problem on x86_64.
However, the problem also affects arm, arm64, riscv, riscv64 and
loongarch. The fix I proposed (i.e. test __DISABLE_EXPORTS) works on all
of the affected architectures because
drivers/firmware/efi/libstub/Makefile puts -D__DISABLE_EXPORTS in CFLAGS,
just as arch/x86/boot/compressed/Makefile does.
AFAICT, when I put -UCONFIG_DEBUG_ATOMIC in CFLAGS, it doesn't override
that macro definition autoconf.h. And there is no equivalent of
arch/x86/boot/compressed/misc.h in drivers/firmware/efi/libstub so I can't
simply add #undef CONFIG_DEBUG_ATOMIC there.
If __DISABLE_EXPORTS is not the appropriate macro for this purpose, then
we need a new macro (e.g. __DISABLE_BUG_TABLE) or else we need a new
header, to be included by some unknown set of .c files (that might
accidentally #include bug.h) so that this new header could do #undef
CONFIG_DEBUG_ATOMIC. My inclination is to implement -D__DISABLE_BUG_TABLE
but I'm open to suggestions.
next prev parent reply other threads:[~2025-12-29 8:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-18 4:30 linux-next: build failure after merge of the mm-nonmm-unstable tree Stephen Rothwell
2025-12-21 2:58 ` Finn Thain
2025-12-26 16:45 ` Sasha Levin
2025-12-29 8:56 ` Finn Thain [this message]
2026-01-01 9:21 ` Finn Thain
2026-01-01 17:01 ` Randy Dunlap
2026-01-01 23:15 ` Finn Thain
2026-01-02 7:29 ` Ard Biesheuvel
2026-01-02 22:09 ` Finn Thain
-- strict thread matches above, loose matches on Subject: below --
2026-04-29 9:10 Thierry Reding
2026-03-17 14:32 Mark Brown
2026-03-17 15:06 ` Mathieu Desnoyers
2026-03-17 15:07 ` David CARLIER
2026-02-16 13:58 Mark Brown
2025-11-16 23:23 Stephen Rothwell
2025-11-19 23:14 ` Stephen Rothwell
2025-11-19 23:48 ` Andrew Morton
2025-11-20 8:55 ` Miguel Ojeda
2025-11-20 10:01 ` Alice Ryhl
2025-11-16 22:36 Stephen Rothwell
2025-10-17 13:25 Mark Brown
2025-10-17 21:34 ` Andrew Morton
2025-09-01 1:17 Stephen Rothwell
2025-07-11 0:58 Stephen Rothwell
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