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Wysocki" , Sasha Levin Subject: [PATCH 6.18 0352/1005] ACPI: APEI: Handle repeated SEA error storms Date: Wed, 4 Nov 2026 16:01:25 -0500 Message-ID: <20261104211053.933533814@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Junhao He [ Upstream commit e61487226b7df39e5f4683b036ee6aa7a5039d7b ] 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 Reviewed-by: Wupeng Ma Reviewed-by: Shuai Xue Reviewed-by: Tony Luck Link: https://patch.msgid.link/20260527082707.2013499-1-hejunhao3@h-partners.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/apei/ghes.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 5b52455d86e02..1a77aba0475be 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -1371,8 +1371,16 @@ static int ghes_in_nmi_queue_one_entry(struct ghes *ghes, ghes_clear_estatus(ghes, &tmp_header, buf_paddr, fixmap_idx); /* This error has been reported before, don't process it again. */ - if (ghes_estatus_cached(estatus)) + if (ghes_estatus_cached(estatus)) { + /* + * Return failure on duplicate SEA entries so that the + * subsequent SEA handler invocation sends a SIGBUS signal to + * the task to prevent it from re-entering the handler loop. + */ + if (is_hest_sync_notify(ghes)) + rc = -ECANCELED; goto no_work; + } llist_add(&estatus_node->llnode, &ghes_estatus_llist); -- 2.53.0