Re: [PATCH v3] x86/fault: Send a SIGBUS to user process always for hwpoison page access.

From: Andy Lutomirski <luto@amacapital.net>
To: Aili Yao <yaoaili@kingsoft.com>
Cc: " HORIGUCHI NAOYA(堀口　直也) " <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
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	[thread overview]
Message-ID: <788DFBA0-903F-4548-9C2F-B1A1543EE770@amacapital.net> (raw)
In-Reply-To: <20210223204436.1df73153@alex-virtual-machine>

> On Feb 23, 2021, at 4:44 AM, Aili Yao <yaoaili@kingsoft.com> wrote:
> 
> On Fri, 5 Feb 2021 17:01:35 +0800
> Aili Yao <yaoaili@kingsoft.com> wrote:
> 
>> 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.
>> 
>> 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.
>> 
>> 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(-)
>> 
> Hi luto;
>  Is there any feedback?

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

> 
> Thanks
> Aili Yao