Re: [PATCH] ACPI: APEI: Handle repeated SEA error interrupts storm scenarios
From: hejunhao
Date: Wed Mar 25 2026 - 05:30:19 EST
On 2026/3/25 10:12, Shuai Xue wrote:
> Hi, junhao
>
> On 3/24/26 6:04 PM, hejunhao wrote:
>> Hi shuai xue,
>>
>>
>> On 2026/3/3 22:42, Shuai Xue wrote:
>>> Hi, junhao,
>>>
>>> On 2/27/26 8:12 PM, hejunhao wrote:
>>>>
>>>>
>>>> On 2025/11/4 9:32, Shuai Xue wrote:
>>>>>
>>>>>
>>>>> 在 2025/11/4 00:19, Rafael J. Wysocki 写道:
>>>>>> On Thu, Oct 30, 2025 at 8:13 AM Junhao He <hejunhao3@xxxxxxxxxxxxxx> wrote:
>>>>>>>
>>>>>>> The do_sea() function defaults to using firmware-first mode, if supported.
>>>>>>> It invoke acpi/apei/ghes ghes_notify_sea() to report and handling the SEA
>>>>>>> error, The GHES uses a buffer to cache the most recent 4 kinds of SEA
>>>>>>> errors. If the same kind SEA error continues to occur, GHES will skip to
>>>>>>> reporting this SEA error and will not add it to the "ghes_estatus_llist"
>>>>>>> list until the cache times out after 10 seconds, at which point the SEA
>>>>>>> error will be reprocessed.
>>>>>>>
>>>>>>> The GHES invoke ghes_proc_in_irq() to handle the SEA error, which
>>>>>>> ultimately executes memory_failure() to process the page with hardware
>>>>>>> memory corruption. If the same SEA error appears multiple times
>>>>>>> consecutively, it indicates that the previous handling was incomplete or
>>>>>>> unable to resolve the fault. In such cases, it is more appropriate to
>>>>>>> return a failure when encountering the same error again, and then proceed
>>>>>>> to arm64_do_kernel_sea for further processing.
>>>
>>> There is no such function in the arm64 tree. If apei_claim_sea() returns
>>
>> Sorry for the mistake in the commit message. The function arm64_do_kernel_sea() should
>> be arm64_notify_die().
>>
>>> an error, the actual fallback path in do_sea() is arm64_notify_die(),
>>> which sends SIGBUS?
>>>
>>
>> If apei_claim_sea() returns an error, arm64_notify_die() will call arm64_force_sig_fault(inf->sig /* SIGBUS */, , , ),
>> followed by force_sig_fault(SIGBUS, , ) to force the process to receive the SIGBUS signal.
>
> So the process is expected to killed by SIGBUS?
Yes. The devmem process is expected to terminate upon receiving a SIGBUS signal, you can
see this at the last line of the test log after the patch is applied.
For other processes whether it terminates depends on whether it catches the signal; the kernel is
responsible for sending it immediately.
>
>>
>>>>>>>
>>>>>>> When hardware memory corruption occurs, a memory error interrupt is
>>>>>>> triggered. If the kernel accesses this erroneous data, it will trigger
>>>>>>> the SEA error exception handler. All such handlers will call
>>>>>>> memory_failure() to handle the faulty page.
>>>>>>>
>>>>>>> If a memory error interrupt occurs first, followed by an SEA error
>>>>>>> interrupt, the faulty page is first marked as poisoned by the memory error
>>>>>>> interrupt process, and then the SEA error interrupt handling process will
>>>>>>> send a SIGBUS signal to the process accessing the poisoned page.
>>>>>>>
>>>>>>> However, if the SEA interrupt is reported first, the following exceptional
>>>>>>> scenario occurs:
>>>>>>>
>>>>>>> When a user process directly requests and accesses a page with hardware
>>>>>>> memory corruption via mmap (such as with devmem), the page containing this
>>>>>>> address may still be in a free buddy state in the kernel. At this point,
>>>>>>> the page is marked as "poisoned" during the SEA claim memory_failure().
>>>>>>> However, since the process does not request the page through the kernel's
>>>>>>> MMU, the kernel cannot send SIGBUS signal to the processes. And the memory
>>>>>>> error interrupt handling process not support send SIGBUS signal. As a
>>>>>>> result, these processes continues to access the faulty page, causing
>>>>>>> repeated entries into the SEA exception handler. At this time, it lead to
>>>>>>> an SEA error interrupt storm.
>>>
>>> In such case, the user process which accessing the poisoned page will be killed
>>> by memory_fauilre?
>>>
>>> // memory_failure():
>>>
>>> if (TestSetPageHWPoison(p)) {
>>> res = -EHWPOISON;
>>> if (flags & MF_ACTION_REQUIRED)
>>> res = kill_accessing_process(current, pfn, flags);
>>> if (flags & MF_COUNT_INCREASED)
>>> put_page(p);
>>> action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
>>> goto unlock_mutex;
>>> }
>>>
>>> I think this problem has already been fixed by commit 2e6053fea379 ("mm/memory-failure:
>>> fix infinite UCE for VM_PFNMAP pfn").
>>>
>>> The root cause is that walk_page_range() skips VM_PFNMAP vmas by default when
>>> no .test_walk callback is set, so kill_accessing_process() returns 0 for a
>>> devmem-style mapping (remap_pfn_range, VM_PFNMAP), making the caller believe
>>> the UCE was handled properly while the process was never actually killed.
>>>
>>> Did you try the lastest kernel version?
>>>
>>
>> I retested this issue on the kernel v7.0.0-rc4 with the following debug patch and was still able to reproduce it.
>>
>>
>> @@ -1365,8 +1365,11 @@ 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)) {
>> + pr_info("This error has been reported before, don't process it again.\n");
>> goto no_work;
>> + }
>>
>> the test log Only some debug logs are retained here.
>>
>> [2026/3/24 14:51:58.199] [root@localhost ~]# taskset -c 40 busybox devmem 0x1351811824 32 0
>> [2026/3/24 14:51:58.369] [root@localhost ~]# taskset -c 40 busybox devmem 0x1351811824 32
>> [2026/3/24 14:51:58.458] [ 130.558038][ C40] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 9
>> [2026/3/24 14:51:58.459] [ 130.572517][ C40] {1}[Hardware Error]: event severity: recoverable
>> [2026/3/24 14:51:58.459] [ 130.578861][ C40] {1}[Hardware Error]: Error 0, type: recoverable
>> [2026/3/24 14:51:58.459] [ 130.585203][ C40] {1}[Hardware Error]: section_type: ARM processor error
>> [2026/3/24 14:51:58.459] [ 130.592238][ C40] {1}[Hardware Error]: MIDR: 0x0000000000000000
>> [2026/3/24 14:51:58.459] [ 130.598492][ C40] {1}[Hardware Error]: Multiprocessor Affinity Register (MPIDR): 0x0000000081010400
>> [2026/3/24 14:51:58.459] [ 130.607871][ C40] {1}[Hardware Error]: error affinity level: 0
>> [2026/3/24 14:51:58.459] [ 130.614038][ C40] {1}[Hardware Error]: running state: 0x1
>> [2026/3/24 14:51:58.459] [ 130.619770][ C40] {1}[Hardware Error]: Power State Coordination Interface state: 0
>> [2026/3/24 14:51:58.459] [ 130.627673][ C40] {1}[Hardware Error]: Error info structure 0:
>> [2026/3/24 14:51:58.459] [ 130.633839][ C40] {1}[Hardware Error]: num errors: 1
>> [2026/3/24 14:51:58.459] [ 130.639137][ C40] {1}[Hardware Error]: error_type: 0, cache error
>> [2026/3/24 14:51:58.459] [ 130.645652][ C40] {1}[Hardware Error]: error_info: 0x0000000020400014
>> [2026/3/24 14:51:58.459] [ 130.652514][ C40] {1}[Hardware Error]: cache level: 1
>> [2026/3/24 14:51:58.551] [ 130.658073][ C40] {1}[Hardware Error]: the error has not been corrected
>> [2026/3/24 14:51:58.551] [ 130.665194][ C40] {1}[Hardware Error]: physical fault address: 0x0000001351811800
>> [2026/3/24 14:51:58.551] [ 130.673097][ C40] {1}[Hardware Error]: Vendor specific error info has 48 bytes:
>> [2026/3/24 14:51:58.551] [ 130.680744][ C40] {1}[Hardware Error]: 00000000: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:51:58.551] [ 130.690471][ C40] {1}[Hardware Error]: 00000010: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:51:58.552] [ 130.700198][ C40] {1}[Hardware Error]: 00000020: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:51:58.552] [ 130.710083][ T9767] Memory failure: 0x1351811: recovery action for free buddy page: Recovered
>> [2026/3/24 14:51:58.638] [ 130.790952][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:51:58.903] [ 131.046994][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:51:58.991] [ 131.132360][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:51:59.969] [ 132.071431][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:00.860] [ 133.010255][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:01.927] [ 134.034746][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:02.906] [ 135.058973][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:03.971] [ 136.083213][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:04.860] [ 137.021956][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:06.018] [ 138.131460][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:06.905] [ 139.070280][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:07.886] [ 140.009147][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 14:52:08.596] [ 140.777368][ C40] {2}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 9
>> [2026/3/24 14:52:08.683] [ 140.791921][ C40] {2}[Hardware Error]: event severity: recoverable
>> [2026/3/24 14:52:08.683] [ 140.798263][ C40] {2}[Hardware Error]: Error 0, type: recoverable
>> [2026/3/24 14:52:08.683] [ 140.804606][ C40] {2}[Hardware Error]: section_type: ARM processor error
>> [2026/3/24 14:52:08.683] [ 140.811641][ C40] {2}[Hardware Error]: MIDR: 0x0000000000000000
>> [2026/3/24 14:52:08.684] [ 140.817895][ C40] {2}[Hardware Error]: Multiprocessor Affinity Register (MPIDR): 0x0000000081010400
>> [2026/3/24 14:52:08.684] [ 140.827274][ C40] {2}[Hardware Error]: error affinity level: 0
>> [2026/3/24 14:52:08.684] [ 140.833440][ C40] {2}[Hardware Error]: running state: 0x1
>> [2026/3/24 14:52:08.684] [ 140.839173][ C40] {2}[Hardware Error]: Power State Coordination Interface state: 0
>> [2026/3/24 14:52:08.684] [ 140.847076][ C40] {2}[Hardware Error]: Error info structure 0:
>> [2026/3/24 14:52:08.684] [ 140.853241][ C40] {2}[Hardware Error]: num errors: 1
>> [2026/3/24 14:52:08.684] [ 140.858540][ C40] {2}[Hardware Error]: error_type: 0, cache error
>> [2026/3/24 14:52:08.684] [ 140.865055][ C40] {2}[Hardware Error]: error_info: 0x0000000020400014
>> [2026/3/24 14:52:08.684] [ 140.871917][ C40] {2}[Hardware Error]: cache level: 1
>> [2026/3/24 14:52:08.684] [ 140.877475][ C40] {2}[Hardware Error]: the error has not been corrected
>> [2026/3/24 14:52:08.764] [ 140.884596][ C40] {2}[Hardware Error]: physical fault address: 0x0000001351811800
>> [2026/3/24 14:52:08.764] [ 140.892499][ C40] {2}[Hardware Error]: Vendor specific error info has 48 bytes:
>> [2026/3/24 14:52:08.766] [ 140.900145][ C40] {2}[Hardware Error]: 00000000: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:52:08.767] [ 140.909872][ C40] {2}[Hardware Error]: 00000010: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:52:08.767] [ 140.919598][ C40] {2}[Hardware Error]: 00000020: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 14:52:08.768] [ 140.929346][ T9767] Memory failure: 0x1351811: already hardware poisoned
>> [2026/3/24 14:52:08.768] [ 140.936072][ T9767] Memory failure: 0x1351811: Sending SIGBUS to busybox:9767 due to hardware memory corruption
>
> Did you cut off some logs here?
I just removed some duplicate debug logs: "This error has already been...", these were added by myself.
> The error log also indicates that the SIGBUS is delivered as expected.
An SError occurs at kernel time 130.558038. Then, after 10 seconds, the kernel
can re-enter the SEA processing flow and send the SIGBUS signal to the process.
This 10-second delay corresponds to the cache timeout threshold of the
ghes_estatus_cached() feature.
Therefore, the purpose of this patch is to send the SIGBUS signal to the process
immediately, rather than waiting for the timeout to expire.
>
>>
>>
>> Apply the patch:
>>
>> @@ -1365,8 +1365,11 @@ 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)) {
>> + pr_info("This error has been reported before, don't process it again.\n");
>> + rc = -ECANCELED;
>> goto no_work;
>> + }
>>
>> [2026/3/24 16:45:40.084] [root@localhost ~]# taskset -c 40 busybox devmem 0x1351811824 32 0
>> [2026/3/24 16:45:40.272] [root@localhost ~]# taskset -c 40 busybox devmem 0x1351811824 32
>> [2026/3/24 16:45:40.362] [ 112.279324][ C40] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 9
>> [2026/3/24 16:45:40.362] [ 112.293797][ C40] {1}[Hardware Error]: event severity: recoverable
>> [2026/3/24 16:45:40.362] [ 112.300139][ C40] {1}[Hardware Error]: Error 0, type: recoverable
>> [2026/3/24 16:45:40.363] [ 112.306481][ C40] {1}[Hardware Error]: section_type: ARM processor error
>> [2026/3/24 16:45:40.363] [ 112.313516][ C40] {1}[Hardware Error]: MIDR: 0x0000000000000000
>> [2026/3/24 16:45:40.363] [ 112.319771][ C40] {1}[Hardware Error]: Multiprocessor Affinity Register (MPIDR): 0x0000000081010400
>> [2026/3/24 16:45:40.363] [ 112.329151][ C40] {1}[Hardware Error]: error affinity level: 0
>> [2026/3/24 16:45:40.363] [ 112.335317][ C40] {1}[Hardware Error]: running state: 0x1
>> [2026/3/24 16:45:40.363] [ 112.341049][ C40] {1}[Hardware Error]: Power State Coordination Interface state: 0
>> [2026/3/24 16:45:40.363] [ 112.348953][ C40] {1}[Hardware Error]: Error info structure 0:
>> [2026/3/24 16:45:40.363] [ 112.355119][ C40] {1}[Hardware Error]: num errors: 1
>> [2026/3/24 16:45:40.363] [ 112.360418][ C40] {1}[Hardware Error]: error_type: 0, cache error
>> [2026/3/24 16:45:40.363] [ 112.366932][ C40] {1}[Hardware Error]: error_info: 0x0000000020400014
>> [2026/3/24 16:45:40.363] [ 112.373795][ C40] {1}[Hardware Error]: cache level: 1
>> [2026/3/24 16:45:40.453] [ 112.379354][ C40] {1}[Hardware Error]: the error has not been corrected
>> [2026/3/24 16:45:40.453] [ 112.386475][ C40] {1}[Hardware Error]: physical fault address: 0x0000001351811800
>> [2026/3/24 16:45:40.453] [ 112.394378][ C40] {1}[Hardware Error]: Vendor specific error info has 48 bytes:
>> [2026/3/24 16:45:40.453] [ 112.402027][ C40] {1}[Hardware Error]: 00000000: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 16:45:40.453] [ 112.411754][ C40] {1}[Hardware Error]: 00000010: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 16:45:40.453] [ 112.421480][ C40] {1}[Hardware Error]: 00000020: 00000000 00000000 00000000 00000000 ................
>> [2026/3/24 16:45:40.453] [ 112.431639][ T9769] Memory failure: 0x1351811: recovery action for free buddy page: Recovered
>> [2026/3/24 16:45:40.531] [ 112.512520][ C40] This error has been reported before, don't process it again.
>> [2026/3/24 16:45:40.757] Bus error (core dumped)
>>
>
>
> Thanks.
> Shuai
>
>
> .
>