From: mawupeng <mawupeng1@huawei•com>
To: <hejunhao3@h-partners•com>, <rafael@kernel•org>,
<tony.luck@intel•com>, <guohanjun@huawei•com>,
<mchehab@kernel•org>, <xueshuai@linux•alibaba.com>,
<jarkko@kernel•org>, <yazen.ghannam@amd•com>,
<jane.chu@oracle•com>, <lenb@kernel•org>, <linmiaohe@huawei•com>
Cc: <mawupeng1@huawei•com>, <bp@alien8•de>,
<linux-acpi@vger•kernel.org>,
<linux-arm-kernel@lists•infradead.org>,
<linux-kernel@vger•kernel.org>, <linux-edac@vger•kernel.org>,
<tanxiaofei@huawei•com>, <linuxarm@huawei•com>,
<liuyonglong@huawei•com>
Subject: Re: [PATCH v2] ACPI: APEI: Handle repeated SEA error storms
Date: Thu, 28 May 2026 09:48:47 +0800 [thread overview]
Message-ID: <e9a85c2f-d720-40a7-90f8-e999e4f0dc22@huawei.com> (raw)
In-Reply-To: <20260527082707.2013499-1-hejunhao3@h-partners.com>
On 周三 2026-5-27 16:27, Junhao He wrote:
> When hardware memory corruption occurs and a user process accesses the
> corrupted page, the CPU triggers a Synchronous External Abort (SEA).
> The kernel invokes do_sea() to handle the exception, which calls
> memory_failure() to handle the faulty page.
>
> Scenario 1: Memory Error Interrupt First, then SEA
> The page is already poisoned by the memory error interrupt path. The
> subsequent SEA handler sends a SIGBUS to the task, which accesses the
> poisoned page. This flow is correct.
>
> Scenario 2: SEA first, then memory error interrupt (problematic scenario)
> If a user task directly accesses corrupted memory through a PFNMAP-style
> mapping (e.g., devmem), the page may still be in the free-buddy state when
> SEA is handled. In this case, memory_failure() will poison the page without
> invoking kill_accessing_process(), and then takes the free-buddy recovery
> path.
>
> After the CPU returns to the task context, the task re-enters the SEA
> handler due to the same access. However, ghes_estatus_cached() suppresses
> all subsequent entries during the 10-second window, preventing
> ghes_do_proc() from being called. This suppression blocks the
> MF_ACTION_REQUIRED-based SIGBUS delivery, causing the kernel to fail to
> kill the task immediately. Consequently, the process keeps re-entering
> the SEA handler, leading to an SEA storm. Later, the memory error
> interrupt path also cannot kill the task, leaving the system stuck in
> this repeated loop.
>
> The following error logs are explained using the devmem process:
> NOTICE: SEA Handle
> [Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 9
> [Hardware Error]: event severity: recoverable
> [Hardware Error]: section_type: ARM processor error
> [Hardware Error]: physical fault address: 0x0000001000093c00
> [T54990] Memory failure: 0x1000093: recovery action for free buddy page: Recovered
> [ T9955] EDAC MC0: 1 UE Multi-bit ECC on unknown memory
> (page:0x1000093 offset:0xc00 grain:1 - APEI location: ...)
> NOTICE: SEA Handle
> NOTICE: SEA Handle
> ...
> ... ---> SEA storm
> ...
> NOTICE: SEA Handle
> [ T9955] Memory failure: 0x1000093: already hardware poisoned
> ghes_print_estatus: 1 callbacks suppressed
> [Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 9
> [Hardware Error]: event severity: recoverable
> [Hardware Error]: section_type: ARM processor error
> [Hardware Error]: physical fault address: 0x0000001000093c00
> [T54990] Memory failure: 0x1000093: already hardware poisoned
> [T54990] 0x1000093: Sending SIGBUS to devmem:54990 due to hardware memory corruption
>
> To resolve this, return an error when encountering the same SEA again.
> The subsequent SEA handler invocation uses arm64_notify_die() to send a
> SIGBUS signal to the task, which terminates the process and prevents it
> from re-entering the handler loop.
>
> Signed-off-by: Junhao He <hejunhao3@h-partners•com>
Reviewed-by: Wupeng Ma <mawupeng1@huawei•com>
prev parent reply other threads:[~2026-05-28 2:34 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 8:27 [PATCH v2] ACPI: APEI: Handle repeated SEA error storms Junhao He
2026-05-28 1:48 ` mawupeng [this message]
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