From: Oleg Nesterov <oleg@redhat.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Elliott Hughes <enh@google.com>,
linux-kernel@vger.kernel.org, linux-um@lists.infradead.org,
llvm@lists.linux.dev, Bill Wendling <morbo@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Justin Stitt <justinstitt@google.com>,
Johannes Berg <johannes@sipsolutions.net>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Richard Weinberger <richard@nod.at>
Subject: Re: [PATCH] x86: uapi: ptrace: guard register offset macros with __ASSEMBLER__ or __FRAME_OFFSETS
Date: Wed, 2 Sep 2026 19:29:09 +0200 [thread overview]
Message-ID: <aphc5Xf0HU0SWcTI@redhat.com> (raw)
In-Reply-To: <CAKwvOdkCGEYWnyJtWT=jArXkA47X==G0PU4UNV=s8htpA3Dg6g@mail.gmail.com>
On 09/01, Nick Desaulniers wrote:
>
> On Fri, Aug 21, 2026 at 3:46 PM Nick Desaulniers
> <ndesaulniers@google.com> wrote:
> >
> > The register offset macros in <asm/ptrace-abi.h> are guarded by
> > `defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)` for 64-bit, but
> > were left unguarded for 32-bit. This causes havoc for userspace that
> > happens to use identifiers colliding with these short macro names
> > (e.g., EBX, ECX, EAX, DS, ES, FS, GS, CS, SS). Without this guard,
> > userspace is forced to be super extra careful with include ordering to
> > minimize the chance of collision.
> >
> > Wrap both the 32-bit and 64-bit register definitions under
> > `#if defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)`, and ensure
> > User-Mode Linux (UML) defines `__FRAME_OFFSETS` for 32-bit as well.
> >
> > Assisted-by: Gemini
> > Link: https://github.com/llvm/llvm-project/issues/217413
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>
> + enh (who pulled this into android for testing)
>
> Oleg, can I get an ack/nack here?
Oh... there is a little problem, I don't understand the usage of
(magic to me) __FRAME_OFFSETS ;)
> Or someone who knows better the
> history of UAPI headers?
Certainly not me....
OK. I'll try to read this patch tomorrow with the clear head after sleep.
Oleg.
prev parent reply other threads:[~2026-09-02 17:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-21 22:45 [PATCH] x86: uapi: ptrace: guard register offset macros with __ASSEMBLER__ or __FRAME_OFFSETS Nick Desaulniers
2026-09-01 21:45 ` Nick Desaulniers
2026-09-02 13:43 ` enh
2026-09-02 17:29 ` Oleg Nesterov [this message]
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