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Message-ID: <0a67888e-6cf4-3a9d-32b1-adbbfcaf2aec@linux.alibaba.com>
Date:   Wed, 26 Oct 2022 13:19:57 +0800
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Subject: Re: [PATCH v3 0/2] Copy-on-write poison recovery
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From:   Shuai Xue <xueshuai@linux.alibaba.com>
To:     Tony Luck <tony.luck@intel.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Miaohe Lin <linmiaohe@huawei.com>,
        Matthew Wilcox <willy@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org
References: <20221019170835.155381-1-tony.luck@intel.com>
 <20221021200120.175753-1-tony.luck@intel.com>
 <85b1b706-c3c2-6316-6dd5-ba1b4306d772@linux.alibaba.com>
In-Reply-To: <85b1b706-c3c2-6316-6dd5-ba1b4306d772@linux.alibaba.com>
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在 2022/10/23 PM11:52, Shuai Xue 写道:
> 
> 
> 在 2022/10/22 AM4:01, Tony Luck 写道:
>> Part 1 deals with the process that triggered the copy on write
>> fault with a store to a shared read-only page. That process is
>> send a SIGBUS with the usual machine check decoration to specify
>> the virtual address of the lost page, together with the scope.
>>
>> Part 2 sets up to asynchronously take the page with the uncorrected
>> error offline to prevent additional machine check faults. H/t to
>> Miaohe Lin <linmiaohe@huawei.com> and Shuai Xue <xueshuai@linux.alibaba.com>
>> for pointing me to the existing function to queue a call to
>> memory_failure().
>>
>> On x86 there is some duplicate reporting (because the error is
>> also signalled by the memory controller as well as by the core
>> that triggered the machine check). Console logs look like this:
>>
>> [ 1647.723403] mce: [Hardware Error]: Machine check events logged
>> 	Machine check from kernel copy routine
>>
>> [ 1647.723414] MCE: Killing einj_mem_uc:3600 due to hardware memory corruption fault at 7f3309503400
>> 	x86 fault handler sends SIGBUS to child process
>>
>> [ 1647.735183] Memory failure: 0x905b92d: recovery action for dirty LRU page: Recovered
>> 	Async call to memory_failure() from copy on write path
> 
> The recovery action might also be handled asynchronously in CMCI uc_decode_notifier
> handler signaled by memory controller, right?
> 
> I have a one more memory failure log than yours.
> 
> [ 3187.485742] MCE: Killing einj_mem_uc:31746 due to hardware memory corruption fault at 7fc4bf7cf400
> [ 3187.740620] Memory failure: 0x1a3b80: recovery action for dirty LRU page: Recovered
> 	uc_decode_notifier() processes memory controller report
> 
> [ 3187.748272] Memory failure: 0x1a3b80: already hardware poisoned
> 	Workqueue: events memory_failure_work_func // queued by ghes_do_memory_failure
> 
> [ 3187.754194] Memory failure: 0x1a3b80: already hardware poisoned
> 	Workqueue: events memory_failure_work_func // queued by __wp_page_copy_user
> 
> [ 3188.615920] MCE: Killing einj_mem_uc:31745 due to hardware memory corruption fault at 7fc4bf7cf400
> 
> Best Regards,
> Shuai

Tested-by: Shuai Xue <xueshuai@linux.alibaba.com>

Thank you.
Shuai

> 
>>
>> [ 1647.748397] Memory failure: 0x905b92d: already hardware poisoned
>> 	uc_decode_notifier() processes memory controller report
>>
>> [ 1647.761313] MCE: Killing einj_mem_uc:3599 due to hardware memory corruption fault at 7f3309503400
>> 	Parent process tries to read poisoned page. Page has been unmapped, so
>> 	#PF handler sends SIGBUS
>>
>>
>> Tony Luck (2):
>>   mm, hwpoison: Try to recover from copy-on write faults
>>   mm, hwpoison: When copy-on-write hits poison, take page offline
>>
>>  include/linux/highmem.h | 24 ++++++++++++++++++++++++
>>  include/linux/mm.h      |  5 ++++-
>>  mm/memory.c             | 32 ++++++++++++++++++++++----------
>>  3 files changed, 50 insertions(+), 11 deletions(-)
>>