[PATCH v17 1/3] ACPI: APEI: send SIGBUS to current task if synchronous memory error not recovered

[Shuai Xue]

在 2024/12/17 07:37, jane.chu at oracle.com 写道:
> 
> On 12/1/2024 7:05 PM, Shuai Xue wrote:
>> Synchronous error was detected as a result of user-space process accessing
>> 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 such as invalid PA,
>> unexpected severity, no memory failure config support, invalid GUID
>> section, etc. In such 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 at linux.alibaba.com>
>> Reviewed-by: Jarkko Sakkinen <jarkko at kernel.org>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron at huawei.com>
>> Reviewed-by: Yazen Ghannam <yazen.ghannam at amd.com>
>> ---
>>   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 a2491905f165..106486bdfefc 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -801,6 +801,17 @@ 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;
>>   }
> 
> Looks good.
> 
> Reviewed-by: Jane Chu <jane.chu at oracle.com>
> 
> -jane

Thanks.

Best Regards,
Shuai