From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>
Cc: kernel test robot <yi1.lai@intel.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org, Finn Thain <fthain@linux-m68k.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Sasha Levin <sashal@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ard Biesheuvel <ardb@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Boqun Feng <boqun.feng@gmail.com>,
Daniel Borkman <daniel@iogearbox.net>,
Dinh Nguyen <dinguyen@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>, Gary Guo <gary@garyguo.net>,
Guo Ren <guoren@kernel.org>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
Jonas Bonn <jonas@southpole.se>, KP Singh <kpsingh@kernel.org>,
Marc Rutland <mark.rutland@arm.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Rich Felker <dalias@libc.org>, Song Liu <song@kernel.org>,
Stafford Horne <shorne@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
Will Deacon <will@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
liam@infradead.org, kas@kernel.org,
Dave Hansen <dave.hansen@intel.com>,
Muhammad Usama Anjum <usama.anjum@arm.com>
Subject: Re: [linus:master] [atomic] 80047d84ee: WARNING:at_include/linux/instrumented.h:#__split_huge_pmd_locked
Date: Tue, 3 Nov 2026 16:58:09 +0100 [thread overview]
Message-ID: <1dbf6b30-15c7-4371-9711-c658a0fc1b50@kernel.org> (raw)
In-Reply-To: <20261103074305.27bfc570fb81346860867bdc@linux-foundation.org>
On 11/3/26 16:43, Andrew Morton wrote:
> On Tue, 3 Nov 2026 13:26:47 +0100 Peter Zijlstra <peterz@infradead.org> wrote:
>
>> AFAICT this is pxx_xchg64() from the PAE code operating on an on-stack
>> pmd value.
>>
>> The below 'fixes' it, but the question is of course, WTF are we using an
>> on-stack pmd value for set_pmd().
>>
>> --- a/arch/x86/include/asm/pgtable-3level_types.h
>> +++ b/arch/x86/include/asm/pgtable-3level_types.h
>> @@ -5,12 +5,12 @@
>> #ifndef __ASSEMBLER__
>> #include <linux/types.h>
>>
>> -typedef u64 pteval_t;
>> -typedef u64 pmdval_t;
>> -typedef u64 pudval_t;
>> -typedef u64 p4dval_t;
>> -typedef u64 pgdval_t;
>> -typedef u64 pgprotval_t;
>> +typedef u64 __aligned(8) pteval_t;
>> +typedef u64 __aligned(8) pmdval_t;
>> +typedef u64 __aligned(8) pudval_t;
>> +typedef u64 __aligned(8) p4dval_t;
>> +typedef u64 __aligned(8) pgdval_t;
>> +typedef u64 __aligned(8) pgprotval_t;
>>
>
> (cc Dave)
>
> fwiw this was discussed a couple of years ago but nothing really came
> of it.
>
> https://lore.kernel.org/20240401185451.6897208962d3fc47a12ffb5a@otheo.eu
IIUC Usama has some things in the works that will avoid on-stack pmds.
--
Cheers,
David
next prev parent reply other threads:[~2026-11-03 15:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-03 0:58 kernel test robot
2026-11-03 9:46 ` Finn Thain
2026-11-03 12:18 ` Arnd Bergmann
2026-11-03 12:26 ` Peter Zijlstra
2026-11-03 12:35 ` Sasha Levin
2026-11-03 12:56 ` Peter Zijlstra
2026-11-03 13:13 ` Arnd Bergmann
2026-11-03 13:41 ` Arnd Bergmann
2026-11-03 14:52 ` Peter Zijlstra
2026-11-03 15:43 ` Andrew Morton
2026-11-03 15:58 ` David Hildenbrand (Arm) [this message]
2026-11-03 16:29 ` Dave Hansen
2026-11-03 16:51 ` Arnd Bergmann
2026-11-03 18:30 ` Dave Hansen
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