From: Thomas Gleixner <tglx@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>, Dmitry Voytik <voytikd@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>,
linux-toolchains@vger.kernel.org,
Alexander Potapenko <glider@google.com>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ankur Arora <ankur.a.arora@oracle.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Marco Elver <elver@google.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
llvm@lists.linux.dev
Subject: Re: [PATCH] x86/mm: fix objtool failure with KMSAN enabled
Date: Thu, 02 Jul 2026 22:05:03 +0200 [thread overview]
Message-ID: <87mrw9nonk.ffs@fw13> (raw)
In-Reply-To: <87se61npie.ffs@fw13>
On Thu, Jul 02 2026 at 21:46, Thomas Gleixner wrote:
> On Thu, Jul 02 2026 at 13:15, Peter Zijlstra wrote:
>> A quick test with folio_zero_user() seems to suggest the
>> ASM_CALL_CONSTRAINT movement (your patch) generates the same code for
>> defconfg as does the unmodified code. The change from the thread linked
>> above (input constraint on __builtin_frame_address(0)) generates
>> different code.
>>
>> A third option is to force FRAME_POINTER=y for KMSAN builds -- for now,
>> until clang is taught to be less insane.
>
> With FRAME_POINTER=y I get now with clang-22
>
> vmlinux.o: warning: objtool: folio_zero_user+0xa7b: stack state mismatch: reg1[4]=-1+0 reg2[4]=-2-336
> vmlinux.o: warning: objtool: set_ftrace_ops_ro+0x64: relocation to !ENDBR: machine_kexec_prepare+0x8f0
>
> That's with your objtool patch applied. When I remove that then the
> folio_zero_user one goes away. The relocation to !ENDBR stays.
>
> Oh well...
And none of this boots when KMSAN=y ....
next prev parent reply other threads:[~2026-07-02 20:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 12:51 [PATCH] x86/mm: fix objtool failure with KMSAN enabled Dmitry Voytik
2026-07-01 13:18 ` Alexander Potapenko
2026-07-01 14:45 ` Dmitry Voytik
2026-07-01 15:15 ` Alexander Potapenko
2026-07-01 22:47 ` Dmitry Voytik
2026-07-02 2:53 ` Borislav Petkov
2026-07-02 10:41 ` Dmitry Voytik
2026-07-02 11:15 ` Peter Zijlstra
2026-07-02 19:46 ` Thomas Gleixner
2026-07-02 20:05 ` Thomas Gleixner [this message]
2026-07-03 10:34 ` Dmitry Voytik
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87mrw9nonk.ffs@fw13 \
--to=tglx@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=ankur.a.arora@oracle.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=hpa@zytor.com \
--cc=jpoimboe@kernel.org \
--cc=justinstitt@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-toolchains@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=mingo@redhat.com \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=nick.desaulniers+lkml@gmail.com \
--cc=peterz@infradead.org \
--cc=voytikd@gmail.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.