From: Linus Torvalds <torvalds@linux-foundation.org>
To: Will Deacon <will@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] x86/uaccess: Fix 32-bit __get_user_asm_u64() when CC_HAS_ASM_GOTO_OUTPUT=y
Date: Mon, 13 Sep 2021 10:05:32 -0700 [thread overview]
Message-ID: <CAHk-=whF01ZS30vQAEjY9K4RM_QNjZ0mTCTt8SY4KuER-2d14w@mail.gmail.com> (raw)
In-Reply-To: <20210913163547.5156-1-will@kernel.org>
On Mon, Sep 13, 2021 at 9:36 AM Will Deacon <will@kernel.org> wrote:
>
> Use the existing '__gu_ptr' source pointer to unsigned int for 32-bit
> __get_user_asm_u64() instead of the original pointer.
Heh. And by "existing" you mean "the one that exists _purely_ for this
exact reason and that wasn't used" ;)
What a silly bug. And it's existed for a year, which I think shows
just how little 32-bit x86 is used these days (*).
Linus
(*) but also probably how few 64-bit user accesses we do - the fact
that the bug was actually found by the "copy_from_kernel_nofault" code
that just shares the infrastructure on x86 rather than any user access
code is kind of interesting.
next prev parent reply other threads:[~2021-09-13 17:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 16:35 [PATCH] x86/uaccess: Fix 32-bit __get_user_asm_u64() when CC_HAS_ASM_GOTO_OUTPUT=y Will Deacon
2021-09-13 16:45 ` Nick Desaulniers
2021-09-13 16:48 ` Greg Kroah-Hartman
2021-09-13 17:05 ` Linus Torvalds [this message]
2021-09-15 7:45 ` Naresh Kamboju
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