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Message-ID: <4f0e830430f46c5f6b90656ec5d3b969d79fe6db.camel@mengyan1223.wang>
Date: Wed, 10 Jul 2019 21:31:35 +0800
From: Xi Ruoyao <xry111@...gyan1223.wang>
To: Jiri Kosina <jikos@...nel.org>,
Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Kees Cook <keescook@...omium.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...nel.org>,
Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
Borislav Petkov <bp@...en8.de>, Len Brown <lenb@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Tony Luck <tony.luck@...el.com>,
Bob Moore <robert.moore@...el.com>,
Erik Schmauss <erik.schmauss@...el.com>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Daniel Bristot de Oliveira <bristot@...hat.com>
Subject: Re: [GIT PULL] x86/topology changes for v5.3
On 2019-07-10 15:28 +0200, Jiri Kosina wrote:
> On Wed, 10 Jul 2019, Jiri Kosina wrote:
> > > > > BUG: unable to handle page fault for address: ffffffff9edc1598
> > > > > #PF: supervisor write access in kernel mode
> > > > > #PF: error_code(0x0003) - permissions violation
> > Hm, and it seems to explode on dereferencing the static_key* in %rsi
>
> ^^^ %rdi of
> course
>
> > 21: 48 8b 37 mov (%rdi),%rsi
> > 24: 83 e6 03 and $0x3,%esi
> > 27: 48 09 c6 or %rax,%rsi
> > 2a:* 48 89 37 mov %rsi,(%rdi) <-- trapping
> > instruction
> >
> > which looks odd, as it derefenced it successfully just 3 instructions ago.
It seems the MMU (I guess ?) allows to read it, but disallows to write it:
"supervisor write access in kernel mode".
--
Xi Ruoyao <xry111@...gyan1223.wang>
School of Aerospace Science and Technology, Xidian University
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