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Date:   Thu, 11 Mar 2021 17:56:58 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Luck, Tony" <tony.luck@intel.com>
Cc:     Andy Lutomirski <luto@amacapital.net>,
        Aili Yao <yaoaili@kingsoft.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Linux API <linux-api@vger.kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
        "yangfeng1@kingsoft.com" <yangfeng1@kingsoft.com>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "sunhao2@kingsoft.com" <sunhao2@kingsoft.com>
Subject: Re: [PATCH v3] x86/fault: Send a SIGBUS to user process always for
 hwpoison page access.
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On Thu, Mar 11, 2021 at 04:52:10PM +0000, Luck, Tony wrote:
> > I think we need to at least fix the existing bug before we add more
> > signals.  AFAICS the MCE_IN_KERNEL_COPYIN code is busted for kernel
> > threads.
> 
> Can a kernel thread do get_user() or copy_from_user()?  Do we have kernel threads
> that have an associated user address space to copy from?

kthread_use_mm()