From: Shuai Xue Date: Mon, 14 Jul 2025 11:42:11 +0000 (+0800) Subject: ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=79a5ae3c4c5eb7e38e0ebe4d6bf602d296080060;p=thirdparty%2Flinux.git ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered If a synchronous error is detected as a result of user-space process triggering a 2-bit uncorrected error, the CPU will take a synchronous error exception such as Synchronous External Abort (SEA) on Arm64. The kernel will queue a memory_failure() work which poisons the related page, unmaps the page, and then sends a SIGBUS to the process, so that a system wide panic can be avoided. However, no memory_failure() work will be queued when abnormal synchronous errors occur. These errors can include situations like invalid PA, unexpected severity, no memory failure config support, invalid GUID section, etc. In such a case, the user-space process will trigger SEA again. This loop can potentially exceed the platform firmware threshold or even trigger a kernel hard lockup, leading to a system reboot. Fix it by performing a force kill if no memory_failure() work is queued for synchronous errors. Signed-off-by: Shuai Xue Reviewed-by: Jarkko Sakkinen Reviewed-by: Jonathan Cameron Reviewed-by: Yazen Ghannam Reviewed-by: Jane Chu Reviewed-by: Hanjun Guo Link: https://patch.msgid.link/20250714114212.31660-2-xueshuai@linux.alibaba.com [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 3d44f926afe8e..bda33a0f0a013 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -902,6 +902,17 @@ static bool ghes_do_proc(struct ghes *ghes, } } + /* + * If no memory failure work is queued for abnormal synchronous + * errors, do a force kill. + */ + if (sync && !queued) { + dev_err(ghes->dev, + HW_ERR GHES_PFX "%s:%d: synchronous unrecoverable error (SIGBUS)\n", + current->comm, task_pid_nr(current)); + force_sig(SIGBUS); + } + return queued; }