What causes this? May 19 02:04:32 kernel: Unhandled fault: alignment fault (0x92000061) at 0x0000000

Router is GT5300 (asus) Here's the log.

May 18 15:15:25 kernel: Unhandled fault: alignment fault (0x92000061) at 0x00000000f41fed73
May 18 16:06:24 kernel: Unhandled fault: alignment fault (0x92000061) at 0x00000000f45ff34f
May 18 16:27:25 kernel: Unhandled fault: alignment fault (0x92000061) at 0x00000000f48ff773
May 18 17:11:08 kernel: Unhandled fault: alignment fault (0x92000061) at 0x00000000f44c65e3
May 18 17:25:04 kernel: Unhandled fault: alignment fault (0x92000061) at...

What causes this? May 19 02:04:32 kernel: Unhandled fault: alignment fault (0x92000061) at 0x0000000