6.6-stable review patch. If anyone has any objections, please let me know.
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From: Shuai Xue xueshuai@linux.alibaba.com
[ Upstream commit 79a5ae3c4c5eb7e38e0ebe4d6bf602d296080060 ]
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 xueshuai@linux.alibaba.com Reviewed-by: Jarkko Sakkinen jarkko@kernel.org Reviewed-by: Jonathan Cameron Jonathan.Cameron@huawei.com Reviewed-by: Yazen Ghannam yazen.ghannam@amd.com Reviewed-by: Jane Chu jane.chu@oracle.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Link: https://patch.msgid.link/20250714114212.31660-2-xueshuai@linux.alibaba.com [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/apei/ghes.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 2abf20736702..22db720b128b 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -715,6 +715,17 @@ 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; }