From: Borislav Petkov <bp@alien8.de>
To: James Morse <james.morse@arm.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>,
Xie XiuQi <xiexiuqi@huawei.com>,
Will Deacon <will.deacon@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Dongjiu Geng <gengdongjiu@huawei.com>,
linux-acpi@vger.kernel.org,
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, 21 Jan 2019 18:58:50 +0100 [thread overview]
Message-ID: <20190121175850.GO29166@zn.tnic> (raw)
In-Reply-To: <20181203180613.228133-23-james.morse@arm.com>
On Mon, Dec 03, 2018 at 06:06:10PM +0000, 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
> to user-space.
>
> Signed-off-by: James Morse <james.morse@arm.com>
>
> ---
> current->mm == &init_mm ? I couldn't find a helper for this.
> The intent is not to set TIF flags on kernel threads. What happens
> if a kernel-thread takes on of these? Its just one of the many
> not-handled-very-well cases we have already, as memory_failure()
> puts it: "try to be lucky".
>
> I assume that if NOTIFY_NMI is coming from SMM it must suffer from
> this problem too.
Good question.
I'm guessing all those things should be queued on a normal struct
work_struct queue, no?
Now, memory_failure_queue() does that and can run from IRQ context so
you need only an irq_work which can queue from NMI context. We do it
this way in the MCA code:
We queue in an irq_work in NMI context and work through the items in
process context.
> ---
> drivers/acpi/apei/ghes.c | 65 ++++++++++++++++++++++++++++++++++++----
> 1 file changed, 60 insertions(+), 5 deletions(-)
...
> @@ -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);
> -#endif
> +
> + /*
> + * If the notification indicates that it was the interrupted
> + * instruction that caused the error, try to kick the
> + * memory_failure() queue before returning to user-space.
> + */
> + if (ghes_is_synchronous(ghes) && current->mm != &init_mm) {
> + callback = kzalloc(sizeof(*callback), GFP_ATOMIC);
Can we avoid that GFP_ATOMIC allocation and kfree() in
ghes_kick_memory_failure()?
I mean, that struct ghes_memory_failure_work is small enough and we
already do lockless allocation:
estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
so I guess we could add that ghes_memory_failure_work struct to that
estatus_node, hand it into ghes_do_proc() and then free it.
No?
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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next prev parent reply other threads:[~2019-01-21 17:59 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
2019-01-22 10:51 ` Borislav Petkov
2019-01-23 18:37 ` James Morse
2019-01-21 17:58 ` Borislav Petkov [this message]
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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