From: James Morse <james.morse@arm.com>
To: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
Tony Luck <tony.luck@intel.com>, Fan Wu <wufan@codeaurora.org>,
linux-mm@kvack.org, Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Dongjiu Geng <gengdongjiu@huawei.com>,
Wang Xiongfeng <wangxiongfeng2@huawei.com>,
linux-acpi@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v7 22/25] ACPI / APEI: Kick the memory_failure() queue for synchronous errors
Date: Mon, 10 Dec 2018 19:15:13 +0000 [thread overview]
Message-ID: <5c775aa9-ea57-dea7-6083-c1e3fc160b29@arm.com> (raw)
In-Reply-To: <9d153a07-aa7a-6e0c-3bd3-994a66f9639a@huawei.com>
Hi Xie XiuQi,
On 05/12/2018 02:02, Xie XiuQi wrote:
> On 2018/12/4 2:06, James Morse wrote:
>> memory_failure() offlines or repairs pages of memory that have been
>> discovered to be corrupt. These may be detected by an external
>> component, (e.g. the memory controller), and notified via an IRQ.
>> In this case the work is queued as not all of memory_failure()s work
>> can happen in IRQ context.
>>
>> If the error was detected as a result of user-space accessing a
>> corrupt memory location the CPU may take an abort instead. On arm64
>> this is a 'synchronous external abort', and on a firmware first
>> system it is replayed using NOTIFY_SEA.
>>
>> This notification has NMI like properties, (it can interrupt
>> IRQ-masked code), so the memory_failure() work is queued. If we
>> return to user-space before the queued memory_failure() work is
>> processed, we will take the fault again. This loop may cause platform
>> firmware to exceed some threshold and reboot when Linux could have
>> recovered from this error.
>>
>> If a ghes notification type indicates that it may be triggered again
>> when we return to user-space, use the task-work and notify-resume
>> hooks to kick the relevant memory_failure() queue before returning
>> @@ -407,7 +447,22 @@ static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, int
>>
>> if (flags != -1)
>> memory_failure_queue(pfn, flags);
>
> We may need to take MF_ACTION_REQUIRED flags for memory_failure() in SEA condition.
Hmmm, I'd forgotten about the extra flags. They're only used by x86's
do_machine_check(), which knows more about what is going on. I agree we do know
it should be a 'MF_ACTION_REQUIRED' for Synchronous-external-abort, but I'd
really like all the notifications to behave in the same way as we can't change
which notification firmware uses.
(This ghes_is_synchronous() affects when memory_failure() runs, not what it does.)
What happens if we miss MF_ACTION_REQUIRED? Surely the page still gets unmapped
as its PG_Poisoned, an AO signal may be pending, but if user-space touches the
page it will get an AR signal. Is this just about removing an extra AO signal to
user-space?
If we do need this, I'd like to pick it up from the CPER records, as x86's
NOTIFY_NMI looks like it covers both AO/AR cases. (as does NOTIFY_SDEI). The
Master/Target abort or Invalid-address types in the memory-error-section CPER
records look like the best bet.
> And there is no return value check for memory_failure() in memory_failure_work_func(),
> I'm not sure whether we need to check the return value.
What would we do if it fails? The reasons look fairly broad, -EBUSY can mean
"(page) still referenced by [..] users", 'thp split failed' or 'page already
poisoned'. I don't think the behaviour or return-codes are consistent enough to use.
> If the recovery fails here, we need to take other actions, such as force to send a SIGBUS signal.
We don't do this today. If it fixes some mis-behaviour, and we can key it from
something in the CPER records then I'm all ears!
Thanks,
James
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next prev parent reply other threads:[~2018-12-10 19:15 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 18:05 [PATCH v7 00/25] APEI in_nmi() rework and SDEI wire-up James Morse
2018-12-03 18:05 ` [PATCH v7 01/25] ACPI / APEI: Don't wait to serialise with oops messages when panic()ing James Morse
2018-12-03 18:05 ` [PATCH v7 02/25] ACPI / APEI: Remove silent flag from ghes_read_estatus() James Morse
2018-12-04 11:36 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 03/25] ACPI / APEI: Switch estatus pool to use vmalloc memory James Morse
2018-12-04 13:01 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 04/25] ACPI / APEI: Make hest.c manage the estatus memory pool James Morse
2018-12-11 16:48 ` Borislav Petkov
2018-12-14 13:56 ` James Morse
2018-12-19 14:42 ` Borislav Petkov
2019-01-10 18:20 ` James Morse
2018-12-03 18:05 ` [PATCH v7 05/25] ACPI / APEI: Make estatus pool allocation a static size James Morse
2018-12-11 16:54 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 06/25] ACPI / APEI: Don't store CPER records physical address in struct ghes James Morse
2018-12-11 17:04 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 07/25] ACPI / APEI: Remove spurious GHES_TO_CLEAR check James Morse
2018-12-11 17:18 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 08/25] ACPI / APEI: Don't update struct ghes' flags in read/clear estatus James Morse
2018-12-03 18:05 ` [PATCH v7 09/25] ACPI / APEI: Generalise the estatus queue's notify code James Morse
2018-12-11 17:44 ` Borislav Petkov
2019-01-10 18:21 ` James Morse
2019-01-11 11:46 ` Borislav Petkov
2018-12-03 18:05 ` [PATCH v7 10/25] ACPI / APEI: Tell firmware the estatus queue consumed the records James Morse
2018-12-11 18:36 ` Borislav Petkov
2019-01-10 18:22 ` James Morse
2019-01-10 21:01 ` Tyler Baicar
2019-01-11 12:03 ` Borislav Petkov
2019-01-11 15:32 ` Tyler Baicar
2019-01-11 17:45 ` Borislav Petkov
2019-01-11 18:25 ` James Morse
2019-01-11 19:58 ` Borislav Petkov
2019-01-23 18:36 ` James Morse
2019-01-29 11:49 ` Borislav Petkov
2019-01-29 18:48 ` James Morse
2019-01-31 13:29 ` Borislav Petkov
2019-01-11 18:09 ` James Morse
2019-01-11 20:01 ` Borislav Petkov
2019-01-11 20:53 ` Tyler Baicar
2019-01-29 18:48 ` James Morse
2018-12-03 18:05 ` [PATCH v7 11/25] ACPI / APEI: Move NOTIFY_SEA between the estatus-queue and NOTIFY_NMI James Morse
2019-01-21 13:01 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 12/25] ACPI / APEI: Switch NOTIFY_SEA to use the estatus queue James Morse
2018-12-03 18:06 ` [PATCH v7 13/25] KVM: arm/arm64: Add kvm_ras.h to collect kvm specific RAS plumbing James Morse
2018-12-06 16:17 ` Catalin Marinas
2018-12-03 18:06 ` [PATCH v7 14/25] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface James Morse
2018-12-06 16:17 ` Catalin Marinas
2018-12-03 18:06 ` [PATCH v7 15/25] ACPI / APEI: Move locking to the notification helper James Morse
2018-12-03 18:06 ` [PATCH v7 16/25] ACPI / APEI: Let the notification helper specify the fixmap slot James Morse
2018-12-03 18:06 ` [PATCH v7 17/25] ACPI / APEI: Pass ghes and estatus separately to avoid a later copy James Morse
2019-01-21 13:35 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 18/25] ACPI / APEI: Split ghes_read_estatus() to allow a peek at the CPER length James Morse
2019-01-21 13:53 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 19/25] ACPI / APEI: Only use queued estatus entry during _in_nmi_notify_one() James Morse
2019-01-21 17:19 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 20/25] ACPI / APEI: Use separate fixmap pages for arm64 NMI-like notifications James Morse
2019-01-21 17:27 ` Borislav Petkov
2019-01-23 18:33 ` James Morse
2019-01-31 13:38 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 21/25] mm/memory-failure: Add memory_failure_queue_kick() James Morse
2018-12-03 18:06 ` [PATCH v7 22/25] ACPI / APEI: Kick the memory_failure() queue for synchronous errors James Morse
2018-12-05 2:02 ` Xie XiuQi
2018-12-10 19:15 ` James Morse [this message]
2019-01-22 10:51 ` Borislav Petkov
2019-01-23 18:37 ` James Morse
2019-01-21 17:58 ` Borislav Petkov
2019-01-23 18:40 ` James Morse
2019-01-31 14:04 ` Borislav Petkov
2018-12-03 18:06 ` [PATCH v7 23/25] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work James Morse
2018-12-06 16:18 ` Catalin Marinas
2018-12-03 18:06 ` [PATCH v7 24/25] firmware: arm_sdei: Add ACPI GHES registration helper James Morse
2018-12-06 16:18 ` Catalin Marinas
2018-12-03 18:06 ` [PATCH v7 25/25] ACPI / APEI: Add support for the SDEI GHES Notification type James Morse
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