Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
From:   Andy Lutomirski <luto@amacapital.net>
Mime-Version: 1.0 (1.0)
Subject: Re: [PATCH v3] x86/fault: Send a SIGBUS to user process always for hwpoison page access.
Date:   Tue, 23 Feb 2021 07:33:46 -0800
Message-Id: <788DFBA0-903F-4548-9C2F-B1A1543EE770@amacapital.net>
References: <20210223204436.1df73153@alex-virtual-machine>
Cc:     =?utf-8?Q?
         "HORIGUCHI_NAOYA=28=E5=A0=80=E5=8F=A3=E3=80=80=E7=9B=B4?=
        =?utf-8?Q?=E4=B9=9F=29" ?= <naoya.horiguchi@nec.com>,
        tony.luck@intel.com, dave.hansen@linux.intel.com, luto@kernel.org,
        peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, hpa@zytor.com, x86@kernel.org,
        yangfeng1@kingsoft.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
In-Reply-To: <20210223204436.1df73153@alex-virtual-machine>
To:     Aili Yao <yaoaili@kingsoft.com>
Precedence: bulk


> On Feb 23, 2021, at 4:44 AM, Aili Yao <yaoaili@kingsoft.com> wrote:
>=20
> =EF=BB=BFOn Fri, 5 Feb 2021 17:01:35 +0800
> Aili Yao <yaoaili@kingsoft.com> wrote:
>=20
>> When one page is already hwpoisoned by MCE AO action, processes may not
>> be killed, processes mapping this page may make a syscall include this
>> page and result to trigger a VM_FAULT_HWPOISON fault, as it's in kernel
>> mode it may be fixed by fixup_exception, current code will just return
>> error code to user code.
>>=20
>> This is not sufficient, we should send a SIGBUS to the process and log
>> the info to console, as we can't trust the process will handle the error
>> correctly.
>>=20
>> Suggested-by: Feng Yang <yangfeng1@kingsoft.com>
>> Signed-off-by: Aili Yao <yaoaili@kingsoft.com>
>> ---
>> arch/x86/mm/fault.c | 62 +++++++++++++++++++++++++++++----------------
>> 1 file changed, 40 insertions(+), 22 deletions(-)
>>=20
> Hi luto;
>  Is there any feedback?

At the very least, this needs a clear explanation of why your proposed behav=
ior is better than the existing behavior.

>=20
> Thanks
> Aili Yao