Supermicro BMC 看门狗导致的重启

Question

我最近买了一块 SuperMicro X10SLL-F 主板，它内置了 BMC（Aspeed AST2400 芯片）。我想在服务器上运行 linux 时使用内置的看门狗控制器（gentoo hardened）。

我在 bios 中启用了看门狗功能，然后将主板跳线从硬复位切换到 NMI（看门狗超时操作，用于测试目的以避免重新启动）。关于软——我安装并添加到默认的运行级别看门狗程序 (sys-apps/watchdog)，该程序被配置为每 10 秒 ping 看门狗设备（/dev/watchdog，存在）。看门狗超时设置为 250 秒。

程序显然可以看到看门狗硬件（启用了 openipmi 的 ipmitool）：

# ipmitool mc watchdog get
Watchdog Timer Use:     SMS/OS (0x44)
Watchdog Timer Is:      Started/Running
Watchdog Timer Actions: Hard Reset (0x01)
Pre-timeout interval:   0 seconds
Timer Expiration Flags: 0x10
Initial Countdown:      254 sec
Present Countdown:      253 sec

免费ipmi：

# bmc-watchdog --get
Timer Use:                   SMS/OS
Timer:                       Running
Logging:                     Enabled
Timeout Action:              Hard Reset
Pre-Timeout Interrupt:       None
Pre-Timeout Interval:        0 seconds
Timer Use BIOS FRB2 Flag:    Clear
Timer Use BIOS POST Flag:    Clear
Timer Use BIOS OS Load Flag: Clear
Timer Use BIOS SMS/OS Flag:  Set
Timer Use BIOS OEM Flag:     Clear
Initial Countdown:           254 seconds
Current Countdown:           253 seconds

但是，经过一段时间后，我得到了（上面程序报告了良好的“当前倒计时”值）：

[  294.107534] Uhhuh. NMI received for unknown reason 21 on CPU 0.
[  294.107998] Do you have a strange power saving mode enabled?
[  294.108437] Dazed and confused, but trying to continue

这是NMI，显然是看门狗超时引起的。在那台机器硬重置发生后不到一分钟。

问题出在哪里，我应该向哪个方向挖掘？

编辑：与 ipmi 相关的内核消息：

[    0.353090] ipmi message handler version 39.2
[    0.353353] ipmi device interface
[    0.353623] IPMI System Interface driver.
[    0.353898] ipmi_si: probing via ACPI
[    0.354172] ipmi_si 00:08: [io  0x0ca2] regsize 1 spacing 1 irq 0
[    0.354444] ipmi_si: Adding ACPI-specified kcs state machine
[    0.354790] ipmi_si: probing via SMBIOS
[    0.355051] ipmi_si: SMBIOS: io 0xca2 regsize 1 spacing 1 irq 0
[    0.355317] ipmi_si: Adding SMBIOS-specified kcs state machine duplicate interface
[    0.355836] ipmi_si: probing via SPMI
[    0.356095] ipmi_si: SPMI: io 0xca2 regsize 1 spacing 1 irq 0
[    0.356362] ipmi_si: Adding SPMI-specified kcs state machine duplicate interface
[    0.356906] ipmi_si: Trying ACPI-specified kcs state machine at i/o address 0xca2, slave address 0x0, irq 0
[    0.390536] ipmi_si: The BMC does not support clearing the recv irq bit, compensating, but the BMC needs to be fixed.
[    0.418476] ipmi_si 00:08: Found new BMC (man_id: 0x002a7c, prod_id: 0x0801, dev_id: 0x20)
[    0.419004] ipmi_si 00:08: IPMI kcs interface initialized
[    0.419272] IPMI SSIF Interface driver
[    0.420350] IPMI Watchdog: driver initialized
[    0.420635] Copyright (C) 2004 MontaVista Software - IPMI Powerdown via sys_reboot.
[    0.421444] IPMI poweroff: ATCA Detect mfg 0x2A7C prod 0x801
[    0.421710] IPMI poweroff: Found a chassis style poweroff function

编辑：我尝试将 bmc-watchdog 与配置“-u 4 -p 2 -a 0 -F -P -L -O -i 300 -e 10”一起使用。所以只使用 SMS/OS 时间，超时前中断设置为 NMI，超时操作设置为 NONE：

# bmc-watchdog --get
Timer Use:                   SMS/OS
Timer:                       Running
Logging:                     Enabled
Timeout Action:              None
Pre-Timeout Interrupt:       NMI / Diagnostic Interrupt
Pre-Timeout Interval:        0 seconds
Timer Use BIOS FRB2 Flag:    Clear
Timer Use BIOS POST Flag:    Clear
Timer Use BIOS OS Load Flag: Clear
Timer Use BIOS SMS/OS Flag:  Set
Timer Use BIOS OEM Flag:     Clear
Initial Countdown:           300 seconds
Current Countdown:           290 seconds

但这根本没有导致任何变化。

编辑。此外，当我触发看门狗定时器时，将 \0x00 回显到 /dev/watchdog 然后保持不变——系统在默认 10 秒超时后正确重启。所以看门狗工作良好，但在启动系统重新启动后正好 350 秒。

编辑。我检查了 BMC 系统事件日志 (SEL) 并在重新启动后发现：

Sensor #202 | Watchdog 2 | Assertion Event | Timer interrupt ; Timer use at expiration = SMS/OS ; Interrupt type = none
Sensor #202 | Watchdog 2 | Assertion Event | Timer expired, status only ; Timer use at expiration = SMS/OS ; Interrupt type = none

有趣的是，该事件标记为“仅限状态”。即便如此，系统也会重新启动。当我故意触发看门狗超时时，日志是不同的：

Sensor #202 | Watchdog 2 | Assertion Event | Timer interrupt ; Timer use at expiration = SMS/OS ; Interrupt type = none
Sensor #202 | Watchdog 2 | Assertion Event | Hard Reset ; Timer use at expiration = SMS/OS ; Interrupt type = none

Answer 1

最终，我找到了一个有点奇怪的解决方案：让看门狗跳线 (JWD1) 保持打开状态（既不选择 NMI 也不选择硬复位）。看门狗在 BIOS 设置中启用。

在这种情况下，看门狗按预期工作——系统在 bmc-watchdog 运行的情况下稳定了 25 分钟，并在看门狗程序终止后重新启动。