1. Run the echo c > /proc/sysrq-trigger command to crash the system. Then errors in Figure 1 may occur.
2. Based on the dmesg information, the problem is caused because the mptsas driver is loaded for about 10 minutes (30s by default).
3. The system is crashed and enters the kdump process. The process finds storage devices. The input/output (I/O) Advanced Programmable Interrupt Controller (APIC) receives the interruption from a device related to the I/O APIC, generates interruption information, and sends the interruption information to the local APIC of the processor. After processing the information, the processor drives the device. Then use the read partition information to identify storage devices in partitions and mount the root partition. See Figure 2.
Figure 2 Process for handling system crash
4. In kdump, the memory in the core serves as the crash storage kernel, and only one processor is reserved. When the I/O APIC distributes the interruption information, an incorrect operation occurs, that is, the information is sent to the local APIC of a nonexistent processor, which causes failures in distributing the interruption information. The driver accesses the sda6 root partition in cycled mode. When the accessing times out, the driver stops accessing the partition, and a message showing that the information is sent to a nonexistent processor is displayed.