This article explains how recurring SATA related kernel errors on an FPC are directly linked to the Buffer I/O error and CPU_CMERROR_STORAGE_ACCESS_ERROR alarm. It describes the symptoms observed in system logs, explains the underlying cause, and provides the recommended resolution.
CPU_CMERROR_STORAGE_ACCESS_ERROR
The issue is caused by instability in the FPC’s local SATA storage, where the drive intermittently becomes unavailable, leading to repeated I/O failures and CPU storage access errors. The following logs and errors may be observed when the FPC storage device is impacted:
1- Below repeated ATA kernel error logs on the FPC: These errors may persist even after an FPC restart, indicating that the underlying issue is not transient
Jan 26 12:00:47 : %PFE-3: fpc7 kern.err kernel:ata1: exception Emask 0x10 SAct 0x0 SErr 0x4090000 action 0xe frozen
Jan 26 12:00:47 : %PFE-3: fpc7 kern.err kernel:ata1: irq_stat 0x00400040, connection status changed
Jan 26 12:00:47 : %PFE-3: fpc7 kern.err kernel:ata1: SError: { PHYRdyChg 10B8B DevExch }
Jan 26 12:00:47 : %PFE-6: fpc7 kern.info kernel:ata1: hard resetting link
Jan 26 12:00:48 : %PFE-6: fpc7 kern.info kernel:ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
Jan 26 12:00:48 : %PFE-6: fpc7 kern.info kernel:ata1.00: configured for UDMA/33
Jan 26 12:00:48 : %PFE-6: fpc7 kern.info kernel:ata1: EH complete
Jan 26 12:01:08 : %PFE-3: fpc7 kern.err kernel:ata1: exception Emask 0x10 SAct 0x0 SErr 0x4090000 action 0xe frozen
Jan 26 12:01:08 : %PFE-3: fpc7 kern.err kernel:ata1: irq_stat 0x00400040, connection status changed
Jan 26 12:01:08 : %PFE-3: fpc7 kern.err kernel:ata1: SError: { PHYRdyChg 10B8B DevExch }
Jan 26 12:01:08: %PFE-6: fpc7 kern.info kernel:ata1: hard resetting link
Jan 26 12:01:09 : %PFE-6: fpc7 kern.info kernel:ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
Jan 26 12:01:09 : %PFE-6: fpc7 kern.info kernel:ata1.00: configured for UDMA/33
Jan 26 12:01:09 : %PFE-6: fpc7 kern.info kernel:ata1: EH complete
2- Buffer I/O error: These errors indicate that the FPC CPU cannot successfully read from or write to the storage device.
Jan 12 14:46:48 : %PFE-3: fpc7 kern.err kernel:blk_update_request: I/O error, dev sda, sector 17239976
Jan 12 14:46:48: %PFE-4: fpc7 kern.warning kernel:EXT4-fs warning (device sda3): ext4_end_bio:314: I/O error -5 writing to inode 130056 (offset 5713920 size 4096 starting block 1124468)
Jan 12 14:46:48 : %PFE-3: fpc7 kern.err kernel:Buffer I/O error on device sda3, logical block 593266
Jan 12 14:46:48 : %PFE-3: fpc7 kern.err kernel:Buffer I/O error on device sda3, logical block 593267
Jan 12 14:46:48 : %PFE-4: fpc7 kern.warning kernel:EXT4-fs warning (device sda3): ext4_end_bio:314: I/O error -5 writing to inode 130088 (offset 0 size 0 starting block 1127317)
Jan 12 14:46:48 : %PFE-3: fpc7 kern.err kernel:Buffer I/O error on device sda3, logical block 596116
Jan 12 14:46:48 : %PFE-4: fpc7 kern.warning kernel:EXT4-fs warning (device sda3): ext4_end_bio:314: I/O error -5 writing to inode 130058 (offset 0 size 0 starting block 1130982)
Jan 12 14:46:48 : %PFE-3: fpc7 kern.err kernel:Buffer I/O error on device sda3, logical block 599781
3- In addition, the FPC may raise the CPU_CMERROR_STORAGE_ACCESS_ERROR alarm when the CPU cannot reliably access its local storage due to repeated I/O failures. This alarm on FPC7 is directly linked to the storage issues observed in the kernel logs
Jan 12 14:47:02 : %PFE-5: fpc7 CMError: /fpc/7/pfe/0/cm/0/Storage_Device/0/CPU_CMERROR_STORAGE_ACCESS_ERROR (0x2c0003), scope: board, category: storage, severity: minor, module: Storage Device , type: Storage access error
1- Restart the FPC to clear the storage error;
2- However, if the kernel logs continue to repeat after the reboot, this confirms a persistent hardware failure.
2026-02-09 : Article Created
2026-06-14 : Mark to be external