The router extended the overlay through a USB device, and after that, the system would restart from time to time after more than 10 days. The router does not have any scheduled tasks. Since the system log is cleared after each restart, I don't know how to locate the fault?
In addition, you can sometimes see the following log before the device restarts
...
usb 1-1: device descriptor read/64, error
...
daemon.err hostapd: ...
...
kern.err kernel: [ 26.669221] blk_update_request: I/O error, dev mtdblock0, sector 16
kern.err kernel: [ 26.721564] blk_update_request: I/O error, dev mtdblock0, sector 120
kern.err kernel: [ 26.746073] blk_update_request: I/O error, dev mtdblock0, sector 120
kern.err kernel: [ 26.752539] Buffer I/O error on dev mtdblock0, logical block 15, async page read
kern.err kernel: [ 26.784012] blk_update_request: I/O error, dev mtdblock0, sector 120
kern.err kernel: [ 26.790476] Buffer I/O error on dev mtdblock0, logical block 15, async page read
kern.err kernel: [ 27.035361] blk_update_request: I/O error, dev mtdblock4, sector 32
kern.err kernel: [ 27.053381] blk_update_request: I/O error, dev mtdblock4, sector 40
kern.err kernel: [ 27.077240] blk_update_request: I/O error, dev mtdblock4, sector 128
kern.err kernel: [ 27.092646] blk_update_request: I/O error, dev mtdblock4, sector 128
kern.err kernel: [ 27.099109] Buffer I/O error on dev mtdblock4, logical block 16, async page read
kern.err kernel: [ 27.171238] blk_update_request: I/O error, dev mtdblock4, sector 128
kern.err kernel: [ 27.177702] Buffer I/O error on dev mtdblock4, logical block 16, async page read
kern.err kernel: [ 27.365285] blk_update_request: I/O error, dev mtdblock7, sector 88
kern.err kernel: [ 27.398742] Buffer I/O error on dev mtdblock7, logical block 462, async page read
kern.err kernel: [ 27.542394] Buffer I/O error on dev mtdblock9, logical block 11, async page read
daemon.err block: /dev/ubiblock0_0 is already mounted on /rom
daemon.err block: /dev/sda1 is already mounted on /overlay
daemon.err block: /dev/sda2 is already mounted on ***
I judge that the failure is roughly in three aspects:
- The router's USB device controller or driver is faulty.
- There is a problem with the external USB device.
- WIFI device failure.
- There is a problem with the pppd service, because there is log information that the operator forces PPPOE to drop and redial.