From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Salvatore Bonaccorso <carnil@debian.org>
Cc: stable@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Sasha Levin <sashal@kernel.org>,
Aboorva Devarajan <aboorvad@linux.ibm.com>,
ritesh.list@gmail.com, hbathini@linux.ibm.com,
mpe@ellerman.id.au, regressions@lists.linux.dev, benh@debian.org
Subject: Re: [regression 6.1.y] Backport of 353d7a84c214f18 ("powerpc/64s/radix/kfence: map __kfence_pool at page granularity") to stable versions 6.1 causes build failure
Date: Sat, 17 Jan 2026 16:39:11 +0100 [thread overview]
Message-ID: <2026011705-turbulent-scheme-71ef@gregkh> (raw)
In-Reply-To: <aWqmDHdHVLs5M3HQ@eldamar.lan>
On Fri, Jan 16, 2026 at 09:56:44PM +0100, Salvatore Bonaccorso wrote:
> Hi,
>
> In v6.1.160 353d7a84c214f18 ("powerpc/64s/radix/kfence: map
> __kfence_pool at page granularity") was backported. But this now
> causes a build failure:
>
> make KERNELRELEASE=6.1.159+ ARCH=powerpc KBUILD_BUILD_VERSION=3 -f ./Makefile
> CALL scripts/checksyscalls.sh
> UPD init/utsversion-tmp.h
> CC init/version.o
> AR init/built-in.a
> CC arch/powerpc/mm/book3s64/radix_pgtable.o
> In file included from arch/powerpc/mm/book3s64/radix_pgtable.c:35:
> ./arch/powerpc/include/asm/kfence.h: In function 'kfence_protect_page':
> ./arch/powerpc/include/asm/kfence.h:37:9: error: implicit declaration of function '__kernel_map_pages'; did you mean 'hash__kernel_map_pages'? [-Werror=implicit-function-declaration]
> 37 | __kernel_map_pages(page, 1, !protect);
> | ^~~~~~~~~~~~~~~~~~
> | hash__kernel_map_pages
> cc1: some warnings being treated as errors
> make[7]: *** [scripts/Makefile.build:250: arch/powerpc/mm/book3s64/radix_pgtable.o] Error 1
> make[6]: *** [scripts/Makefile.build:503: arch/powerpc/mm/book3s64] Error 2
>
> This is because 8f14a96386b2 ("mm: page_poison: always declare
> __kernel_map_pages() function") is missing from 6.1.y (it was only
> included in 6.5-rc1).
>
> Cherry-picking 8f14a96386b2 fixes the build failure on powerpc.
>
> #regzbot introduced 36c1dc122eb3b917cd2c343029ff60a366a00539
>
> Marking as regression for 36c1dc122eb3 ("powerpc/64s/radix/kfence: map
> __kfence_pool at page granularity"), for the 6.1.y specific commit
> causing the regression.
Now queued up, thanks.
greg k-h
prev parent reply other threads:[~2026-01-17 15:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-16 20:56 [regression 6.1.y] Backport of 353d7a84c214f18 ("powerpc/64s/radix/kfence: map __kfence_pool at page granularity") to stable versions 6.1 causes build failure Salvatore Bonaccorso
2026-01-17 15:39 ` Greg Kroah-Hartman [this message]
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