From: Andi Kleen <andi@firstfloor.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Brian Gerst <brgerst@gmail.com>,
Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Byungchul Park <byungchul.park@lge.com>,
Nilay Vaish <nilayvaish@gmail.com>
Subject: Re: [PATCH 5/8] x86/head: remove useless zeroed word
Date: Mon, 22 Aug 2016 14:48:46 -0700 [thread overview]
Message-ID: <87y43ozd8h.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <b056855c295bbb3825b97c1e9f7958539a4d6cf2.1471535549.git.jpoimboe@redhat.com> (Josh Poimboeuf's message of "Thu, 18 Aug 2016 10:59:05 -0500")
Josh Poimboeuf <jpoimboe@redhat.com> writes:
> This zeroed word has no apparent purpose, so remove it.
>
> Brian Gerst says:
>
> "FYI the word used to be the SS segment selector for the LSS
> instruction, which isn't needed in 64-bit mode."
>
Seems dangerous. It wouldn't surprise me if some CPUs or x86 emulations
load it anyways and trigger page faults if there is really nothing
there.
-Andi
next prev parent reply other threads:[~2016-08-22 21:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-18 15:59 [PATCH 0/8] x86: stack-related cleanups and fixes Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 1/8] x86/dumpstack: remove show_trace() Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 2/8] x86/asm/head: remove unused init_rsp variable extern Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 3/8] x86/asm/head: rename 'stack_start' -> 'initial_stack' Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 4/8] x86/dumpstack: remove extra brackets around "<EOE>" Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 5/8] x86/head: remove useless zeroed word Josh Poimboeuf
2016-08-22 21:48 ` Andi Kleen [this message]
2016-08-22 22:23 ` H. Peter Anvin
2016-08-22 22:47 ` Brian Gerst
2016-08-22 23:10 ` H. Peter Anvin
2016-08-22 22:47 ` Linus Torvalds
2016-08-18 15:59 ` [PATCH 6/8] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 7/8] proc: fix return address printk conversion specifer in /proc/<pid>/stack Josh Poimboeuf
2016-08-18 15:59 ` [PATCH 8/8] x86: remove 64-byte gap at end of irq stack Josh Poimboeuf
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