Blk_update_request: I/O errors

Is it normal for dmesg to see Buffer I/O errors triggered simply by running /sbin/block info?

# dmesg
...
[  135.019264] usb 1-1: new high-speed USB device number 2 using xhci-hcd
[  244.586841] blk_update_request: I/O error, dev mtdblock0, sector 0
[  244.587637] blk_update_request: I/O error, dev mtdblock0, sector 8
[  244.593376] blk_update_request: I/O error, dev mtdblock0, sector 16
[  244.599106] blk_update_request: I/O error, dev mtdblock0, sector 24
[  244.605102] blk_update_request: I/O error, dev mtdblock0, sector 0
[  244.610516] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  244.618588] blk_update_request: I/O error, dev mtdblock1, sector 0
[  244.624883] blk_update_request: I/O error, dev mtdblock1, sector 8
[  244.631260] blk_update_request: I/O error, dev mtdblock1, sector 16
[  244.637109] blk_update_request: I/O error, dev mtdblock1, sector 24
[  244.644044] blk_update_request: I/O error, dev mtdblock1, sector 0
[  244.648780] Buffer I/O error on dev mtdblock1, logical block 0, async page read

I had LEDE running for a few days with no USB attached and never saw these errors. Now that I have a USB connected, I am seeing these throughout the dmesg output. My hypothesis is that one of the scripts is calling /sbin/block to trigger them. Hardware is an R7800. Can anyone else confirm these are present?

Looks like bad USB device, kindly check dmesg | tail -n 50 on linux PC, just after inserting this device Compare the output with router log.
Or this could be case of improper USB driver

I verified the USB stick is not the issue; I get the errors with any number of USB sticks. I get no errors when connected to a linux PC. I am able to write out data on it until full dd if=/dev/zero of=/mnt/mini/fill status=progress on the linux PC.

I am thinking this might be a bug on the LEDE... the USB itself is /dev/sda not mtdblock1 or mtdblock0. Those are LEDE rom and overplay mounts:

# block info
/dev/ubiblock0_0: UUID="29145bd1-5d52a1b3-72baec83-0b857884" VERSION="4.0" MOUNT="/rom" TYPE="squashfs"
/dev/ubi0_1: UUID="12aaac53-a4f9-46ef-93ba-7185d5b8013b" VERSION="w4r0" MOUNT="/overlay" TYPE="ubifs"
/dev/sda1: UUID="ca92d326-f075-4b39-b4a9-5d1ddea5b05x" VERSION="1.8" MOUNT="/mnt/sda1" TYPE="f2fs"

Can anyone else using an R7800 confirm this behavior?

No, I have Netgear WNDR4700 or powerpc_464fp or apm821xx

Can you format a USB stick with ext3/4 once, just to test

If I completely remove the USB and execute block info on the router, I get the same output in dmesg. The error messages are triggered by running that it seems.

This is USB related issue (which is no issue actually )

This is internal ROM/NAND related error specific to R7800, read the documentation or openWRT page for your device, and github repository for R7800

Thanks for the reply. I didn't see the R7800 on the OpenWRT page. Which github repo are you referring to?

Well try go through, but it could led waste of time without result https://forum.openwrt.org/viewtopic.php?id=64637
I will send github firmware link too.

I did not found any github repo for your router, like mine.

Thanks for looking...

Can you post a link to the github repo specific to your hardware?

It is maintained by "chunkeey" LEDE forum member , he keep every thing properly documented

https://github.com/lede-project/source/commit/9e0fd1b52ad1f805a308bf6a5a13236f352fd962
https://github.com/lede-project/source/commit/49856a4bb5818146d9cf951cb65a0903d3b38fd4



That's cool. My R7800 is an ipq806x
https://downloads.lede-project.org/releases/17.01.4/targets/ipq806x/generic/

It happens to me also, on some CF cards(I boot from CF), could it be like bad blocks on flash ?
as I remember, I get always the same blocks, after a sysupgrade

My Netgear R7800 obviously is the 3rd reported victim of fresh 17.01.4 release (I built for myself). Please help fix/identify the root of this critical functionality bug. Really appreciate your genius Openwrt/LEDE guys' valuable works, it makes the boring and slow stock router much more versatile.

[    5.708669] usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
[    5.753231] usb-storage 2-1:1.0: USB Mass Storage device detected
[    5.753898] scsi host1: usb-storage 2-1:1.0
[    6.836118] scsi 1:0:0:0: Direct-Access     WD       My Passport 0827 1012 PQ: 0 ANSI: 6
[    6.837451] sd 1:0:0:0: [sda] Spinning up disk...
[    6.843715] scsi 1:0:0:1: Enclosure         WD       SES Device       1012 PQ: 0 ANSI: 6
[    7.850312] ..
[    8.944909] ipq806x-gmac-dwmac 37400000.ethernet eth1: Link is Up - 1Gbps/Full - flow control off
[    9.870791] .
[   10.138161] mount_root: loading kmods from internal overlay
[   10.154943] kmodloader: loading kernel modules from //etc/modules-boot.d/*
[   10.157403] kmodloader: done loading kernel modules from //etc/modules-boot.d/*
[   10.199809] blk_update_request: I/O error, dev mtdblock0, sector 0
[   10.200390] blk_update_request: I/O error, dev mtdblock0, sector 8
[   10.205434] blk_update_request: I/O error, dev mtdblock0, sector 16
[   10.211677] blk_update_request: I/O error, dev mtdblock0, sector 24
[   10.217829] blk_update_request: I/O error, dev mtdblock0, sector 0
[   10.223465] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[   10.232849] blk_update_request: I/O error, dev mtdblock1, sector 0
[   10.237461] blk_update_request: I/O error, dev mtdblock1, sector 8
[   10.243837] blk_update_request: I/O error, dev mtdblock1, sector 16
[   10.250044] blk_update_request: I/O error, dev mtdblock1, sector 24
[   10.256134] blk_update_request: I/O error, dev mtdblock1, sector 0
[   10.261739] Buffer I/O error on dev mtdblock1, logical block 0, async page read

[   12.949379] sd 1:0:0:0: [sda] 3906963456 512-byte logical blocks: (2.00 TB/1.82 TiB)
[   12.950104] sd 1:0:0:0: [sda] Write Protect is off
[   12.957491] sd 1:0:0:0: [sda] Mode Sense: 47 00 10 08
[   12.958999] sd 1:0:0:0: [sda] No Caching mode page found
[   12.962090] sd 1:0:0:0: [sda] Assuming drive cache: write through
[   12.980077] firmware ath10k!pre-cal-pci-0000:01:00.0.bin: firmware_loading_store: map pages failed
[   12.980281] ath10k_pci 0000:01:00.0: Direct firmware load for ath10k/cal-pci-0000:01:00.0.bin failed with error -2
[   12.983737]  sda: sda1
[   12.991312] sd 1:0:0:0: [sda] Attached SCSI disk

[   21.030627] blk_update_request: 10 callbacks suppressed
[   21.030648] blk_update_request: I/O error, dev mtdblock0, sector 0
[   21.035074] blk_update_request: I/O error, dev mtdblock0, sector 8
[   21.041602] blk_update_request: I/O error, dev mtdblock0, sector 16
[   21.047496] blk_update_request: I/O error, dev mtdblock0, sector 24
[   21.102521] blk_update_request: I/O error, dev mtdblock0, sector 0
[   21.102547] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[   21.108193] blk_update_request: I/O error, dev mtdblock1, sector 0
[   21.115315] blk_update_request: I/O error, dev mtdblock1, sector 8
[   21.121538] blk_update_request: I/O error, dev mtdblock1, sector 16
[   21.127874] blk_update_request: I/O error, dev mtdblock1, sector 24
[   21.134008] blk_update_request: I/O error, dev mtdblock1, sector 0
[   21.139618] Buffer I/O error on dev mtdblock1, logical block 0, async page read

it's strange, I don't have these errors on 64 bit target
edit:
so with glibc I have error, with musl I don't

i confirm it with Linksys EA-8500 any kind of disk i am using ,causing this with a huge memory leak and no way to reboot the router, except only by physical buttons! here is my kernel log

[  107.222573] blk_update_request: 40 callbacks suppressed
[  107.222600] blk_update_request: I/O error, dev mtdblock0, sector 0
[  107.228210] blk_update_request: I/O error, dev mtdblock0, sector 8
[  107.233818] blk_update_request: I/O error, dev mtdblock0, sector 16
[  107.239914] blk_update_request: I/O error, dev mtdblock0, sector 24
[  107.246212] blk_update_request: I/O error, dev mtdblock0, sector 0
[  107.251427] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  107.260214] blk_update_request: I/O error, dev mtdblock1, sector 0
[  107.266440] blk_update_request: I/O error, dev mtdblock1, sector 8
[  107.272568] blk_update_request: I/O error, dev mtdblock1, sector 16
[  107.277873] blk_update_request: I/O error, dev mtdblock1, sector 24
[  107.285021] blk_update_request: I/O error, dev mtdblock1, sector 0
[  107.289708] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  107.414442] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  107.416900] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  107.424258] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  107.438058] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  107.440944] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  107.447525] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  107.467710] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  133.050538] blk_update_request: 40 callbacks suppressed
[  133.050566] blk_update_request: I/O error, dev mtdblock0, sector 0
[  133.055245] blk_update_request: I/O error, dev mtdblock0, sector 8
[  133.061735] blk_update_request: I/O error, dev mtdblock0, sector 16
[  133.068256] blk_update_request: I/O error, dev mtdblock0, sector 24
[  133.074503] blk_update_request: I/O error, dev mtdblock0, sector 0
[  133.079396] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  133.086450] blk_update_request: I/O error, dev mtdblock1, sector 0
[  133.094577] blk_update_request: I/O error, dev mtdblock1, sector 8
[  133.100625] blk_update_request: I/O error, dev mtdblock1, sector 16
[  133.106706] blk_update_request: I/O error, dev mtdblock1, sector 24
[  133.169955] blk_update_request: I/O error, dev mtdblock1, sector 0
[  133.169982] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  133.291606] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  133.294160] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  133.301504] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  133.314672] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  133.317472] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  133.324343] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  133.351024] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  144.763478] usb 3-1.3: USB disconnect, device number 3
[  145.787464] usb 3-1.4: USB disconnect, device number 4
[  147.556848] usb 3-1.4: new high-speed USB device number 5 using xhci-hcd
[  148.316193] usb-storage 3-1.4:1.0: USB Mass Storage device detected
[  148.317580] scsi host3: usb-storage 3-1.4:1.0
[  149.317973] scsi 3:0:0:0: Direct-Access                               1.00 PQ: 0 ANSI: 6
[  149.320628] sd 3:0:0:0: [sda] 122880000 512-byte logical blocks: (62.9 GB/58.6 GiB)
[  149.326584] sd 3:0:0:0: [sda] Write Protect is off
[  149.333577] sd 3:0:0:0: [sda] Mode Sense: 23 00 00 00
[  149.338530] sd 3:0:0:0: [sda] Write cache: disabled, read cache: disabled, doesn't support DPO or FUA
[  149.347653]  sda: sda1
[  149.354985] sd 3:0:0:0: [sda] Attached SCSI removable disk
[  150.131684] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: 
[  154.986776] usb 3-1.3: new high-speed USB device number 6 using xhci-hcd
[  155.090060] usb 3-1.3: ep 0x81 - rounding interval to 128 microframes, ep desc says 255 microframes
[  155.090124] usb 3-1.3: ep 0x2 - rounding interval to 128 microframes, ep desc says 255 microframes
[  155.100435] usb-storage 3-1.3:1.0: USB Mass Storage device detected
[  155.112179] scsi host4: usb-storage 3-1.3:1.0
[  156.107712] scsi 4:0:0:0: Direct-Access     Kingston DataTraveler G2  1.00 PQ: 0 ANSI: 2
[  156.110606] sd 4:0:0:0: [sdb] 31252024 512-byte logical blocks: (16.0 GB/14.9 GiB)
[  156.117924] sd 4:0:0:0: [sdb] Write Protect is off
[  156.124971] sd 4:0:0:0: [sdb] Mode Sense: 16 24 09 51
[  156.128124] sd 4:0:0:0: [sdb] Incomplete mode parameter data
[  156.132726] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[  156.142315]  sdb: sdb1 sdb2
[  156.150019] sd 4:0:0:0: [sdb] Attached SCSI removable disk
[  157.189996] EXT4-fs (sdb2): mounted filesystem with ordered data mode. Opts: 
[  160.244231] blk_update_request: 40 callbacks suppressed
[  160.244260] blk_update_request: I/O error, dev mtdblock0, sector 0
[  160.248885] blk_update_request: I/O error, dev mtdblock0, sector 8
[  160.256450] blk_update_request: I/O error, dev mtdblock0, sector 16
[  160.262616] blk_update_request: I/O error, dev mtdblock0, sector 24
[  160.268379] blk_update_request: I/O error, dev mtdblock0, sector 0
[  160.273090] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  160.280698] blk_update_request: I/O error, dev mtdblock1, sector 0
[  160.288925] blk_update_request: I/O error, dev mtdblock1, sector 8
[  160.295746] blk_update_request: I/O error, dev mtdblock1, sector 16
[  160.299876] blk_update_request: I/O error, dev mtdblock1, sector 24
[  160.306353] blk_update_request: I/O error, dev mtdblock1, sector 0
[  160.311370] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  160.447604] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  160.450607] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  160.458173] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  160.470647] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  160.473313] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  160.479630] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  160.500585] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  181.629285] blk_update_request: 40 callbacks suppressed
[  181.629311] blk_update_request: I/O error, dev mtdblock0, sector 0
[  181.633932] blk_update_request: I/O error, dev mtdblock0, sector 8
[  181.640394] blk_update_request: I/O error, dev mtdblock0, sector 16
[  181.647168] blk_update_request: I/O error, dev mtdblock0, sector 24
[  181.653132] blk_update_request: I/O error, dev mtdblock0, sector 0
[  181.658138] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  181.667059] blk_update_request: I/O error, dev mtdblock1, sector 0
[  181.672403] blk_update_request: I/O error, dev mtdblock1, sector 8
[  181.678996] blk_update_request: I/O error, dev mtdblock1, sector 16
[  181.684812] blk_update_request: I/O error, dev mtdblock1, sector 24
[  181.690940] blk_update_request: I/O error, dev mtdblock1, sector 0
[  181.696419] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  181.817195] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  181.819635] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  181.827154] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  181.840785] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  181.843484] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  181.849843] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  181.870182] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  189.974114] blk_update_request: 40 callbacks suppressed
[  189.974140] blk_update_request: I/O error, dev mtdblock0, sector 0
[  189.978754] blk_update_request: I/O error, dev mtdblock0, sector 8
[  189.985519] blk_update_request: I/O error, dev mtdblock0, sector 16
[  189.991526] blk_update_request: I/O error, dev mtdblock0, sector 24
[  189.997516] blk_update_request: I/O error, dev mtdblock0, sector 0
[  190.002972] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  190.011042] blk_update_request: I/O error, dev mtdblock1, sector 0
[  190.017334] blk_update_request: I/O error, dev mtdblock1, sector 8
[  190.024385] blk_update_request: I/O error, dev mtdblock1, sector 16
[  190.030188] blk_update_request: I/O error, dev mtdblock1, sector 24
[  190.037600] blk_update_request: I/O error, dev mtdblock1, sector 0
[  190.041248] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  190.159099] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  190.161955] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  190.168956] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  190.182961] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  190.185620] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  190.192213] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  190.214083] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  191.683364] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  198.267676] usb 3-1.3: USB disconnect, device number 6
[  200.043477] usb 3-1.3: new high-speed USB device number 7 using xhci-hcd
[  200.156453] usb 3-1.3: ep 0x81 - rounding interval to 128 microframes, ep desc says 255 microframes
[  200.156514] usb 3-1.3: ep 0x2 - rounding interval to 128 microframes, ep desc says 255 microframes
[  200.165751] usb-storage 3-1.3:1.0: USB Mass Storage device detected
[  200.174680] scsi host5: usb-storage 3-1.3:1.0
[  201.185455] scsi 5:0:0:0: Direct-Access     Kingston DataTraveler G2  1.00 PQ: 0 ANSI: 2
[  201.188554] sd 5:0:0:0: [sdb] 31252024 512-byte logical blocks: (16.0 GB/14.9 GiB)
[  201.194219] sd 5:0:0:0: [sdb] Write Protect is off
[  201.200126] sd 5:0:0:0: [sdb] Mode Sense: 16 24 09 51
[  201.205644] sd 5:0:0:0: [sdb] Incomplete mode parameter data
[  201.210255] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[  201.219677]  sdb: sdb1 sdb2
[  201.224553] sd 5:0:0:0: [sdb] Attached SCSI removable disk
[  204.537179] blk_update_request: 90 callbacks suppressed
[  204.537205] blk_update_request: I/O error, dev mtdblock0, sector 0
[  204.542148] blk_update_request: I/O error, dev mtdblock0, sector 8
[  204.548892] blk_update_request: I/O error, dev mtdblock0, sector 16
[  204.554996] blk_update_request: I/O error, dev mtdblock0, sector 24
[  204.561390] blk_update_request: I/O error, dev mtdblock0, sector 0
[  204.566032] buffer_io_error: 8 callbacks suppressed
[  204.572280] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  204.578494] blk_update_request: I/O error, dev mtdblock1, sector 0
[  204.585306] blk_update_request: I/O error, dev mtdblock1, sector 8
[  204.591333] blk_update_request: I/O error, dev mtdblock1, sector 16
[  204.597584] blk_update_request: I/O error, dev mtdblock1, sector 24
[  204.603943] blk_update_request: I/O error, dev mtdblock1, sector 0
[  204.609176] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  204.750840] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  204.753838] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  204.760933] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  204.774874] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  204.777825] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  204.784113] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  204.806094] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  209.794298] blk_update_request: 40 callbacks suppressed
[  209.794327] blk_update_request: I/O error, dev mtdblock0, sector 0
[  209.804050] blk_update_request: I/O error, dev mtdblock0, sector 8
[  209.806212] blk_update_request: I/O error, dev mtdblock0, sector 16
[  209.811419] blk_update_request: I/O error, dev mtdblock0, sector 24
[  209.817738] blk_update_request: I/O error, dev mtdblock0, sector 0
[  209.823156] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  209.830276] blk_update_request: I/O error, dev mtdblock1, sector 0
[  209.837300] blk_update_request: I/O error, dev mtdblock1, sector 8
[  209.844433] blk_update_request: I/O error, dev mtdblock1, sector 16
[  209.849766] blk_update_request: I/O error, dev mtdblock1, sector 24
[  209.858477] blk_update_request: I/O error, dev mtdblock1, sector 0
[  209.861445] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  210.011397] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  210.014079] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  210.021471] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  210.034962] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  210.037513] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  210.044038] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  210.066653] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  225.949391] usb 3-1: USB disconnect, device number 2
[  225.949426] usb 3-1.3: USB disconnect, device number 7
[  225.986792] usb 3-1.4: USB disconnect, device number 5
[  229.283848] usb 3-1: new high-speed USB device number 8 using xhci-hcd
[  229.428413] hub 3-1:1.0: USB hub found
[  229.428750] hub 3-1:1.0: 4 ports detected
[  229.703805] usb 3-1.3: new high-speed USB device number 9 using xhci-hcd
[  229.807428] usb 3-1.3: ep 0x81 - rounding interval to 128 microframes, ep desc says 255 microframes
[  229.807481] usb 3-1.3: ep 0x2 - rounding interval to 128 microframes, ep desc says 255 microframes
[  229.818604] usb-storage 3-1.3:1.0: USB Mass Storage device detected
[  229.828419] scsi host6: usb-storage 3-1.3:1.0
[  229.913788] usb 3-1.4: new high-speed USB device number 10 using xhci-hcd
[  230.559291] usb-storage 3-1.4:1.0: USB Mass Storage device detected
[  230.560172] scsi host7: usb-storage 3-1.4:1.0
[  230.824713] scsi 6:0:0:0: Direct-Access     Kingston DataTraveler G2  1.00 PQ: 0 ANSI: 2
[  230.827392] sd 6:0:0:0: [sda] 31252024 512-byte logical blocks: (16.0 GB/14.9 GiB)
[  230.832693] sd 6:0:0:0: [sda] Write Protect is off
[  230.839731] sd 6:0:0:0: [sda] Mode Sense: 16 24 09 51
[  230.844809] sd 6:0:0:0: [sda] Incomplete mode parameter data
[  230.849348] sd 6:0:0:0: [sda] Assuming drive cache: write through
[  230.858537]  sda: sda1 sda2
[  230.863516] sd 6:0:0:0: [sda] Attached SCSI removable disk
[  231.565856] scsi 7:0:0:0: Direct-Access                               1.00 PQ: 0 ANSI: 6
[  231.568874] sd 7:0:0:0: [sdb] 122880000 512-byte logical blocks: (62.9 GB/58.6 GiB)
[  231.575309] sd 7:0:0:0: [sdb] Write Protect is off
[  231.580820] sd 7:0:0:0: [sdb] Mode Sense: 23 00 00 00
[  231.586904] sd 7:0:0:0: [sdb] Write cache: disabled, read cache: disabled, doesn't support DPO or FUA
[  231.598765]  sdb: sdb1
[  231.606186] sd 7:0:0:0: [sdb] Attached SCSI removable disk
[  238.212926] blk_update_request: 40 callbacks suppressed
[  238.212951] blk_update_request: I/O error, dev mtdblock0, sector 0
[  238.218030] blk_update_request: I/O error, dev mtdblock0, sector 8
[  238.224286] blk_update_request: I/O error, dev mtdblock0, sector 16
[  238.230455] blk_update_request: I/O error, dev mtdblock0, sector 24
[  238.237802] blk_update_request: I/O error, dev mtdblock0, sector 0
[  238.241781] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  238.249910] blk_update_request: I/O error, dev mtdblock1, sector 0
[  238.256510] blk_update_request: I/O error, dev mtdblock1, sector 8
[  238.262152] blk_update_request: I/O error, dev mtdblock1, sector 16
[  238.268639] blk_update_request: I/O error, dev mtdblock1, sector 24
[  238.274760] blk_update_request: I/O error, dev mtdblock1, sector 0
[  238.280061] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  238.408867] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  238.411901] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  238.419325] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  238.433081] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  238.435678] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  238.442046] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  238.468860] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  242.867115] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  275.379138] blk_update_request: 90 callbacks suppressed
[  275.379167] blk_update_request: I/O error, dev mtdblock0, sector 0
[  275.387877] blk_update_request: I/O error, dev mtdblock0, sector 8
[  275.390075] blk_update_request: I/O error, dev mtdblock0, sector 16
[  275.396701] blk_update_request: I/O error, dev mtdblock0, sector 24
[  275.403294] blk_update_request: I/O error, dev mtdblock0, sector 0
[  275.407993] buffer_io_error: 8 callbacks suppressed
[  275.414240] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  275.422748] blk_update_request: I/O error, dev mtdblock1, sector 0
[  275.427631] blk_update_request: I/O error, dev mtdblock1, sector 8
[  275.434410] blk_update_request: I/O error, dev mtdblock1, sector 16
[  275.440367] blk_update_request: I/O error, dev mtdblock1, sector 24
[  275.446320] blk_update_request: I/O error, dev mtdblock1, sector 0
[  275.451134] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  275.601776] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  275.605039] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  275.612807] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  275.627671] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  275.630760] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  275.637745] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  275.661814] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  284.726854] blk_update_request: 40 callbacks suppressed
[  284.726891] blk_update_request: I/O error, dev mtdblock0, sector 0
[  284.731699] blk_update_request: I/O error, dev mtdblock0, sector 8
[  284.737945] blk_update_request: I/O error, dev mtdblock0, sector 16
[  284.743892] blk_update_request: I/O error, dev mtdblock0, sector 24
[  284.750246] blk_update_request: I/O error, dev mtdblock0, sector 0
[  284.755718] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  284.762980] blk_update_request: I/O error, dev mtdblock1, sector 0
[  284.772885] blk_update_request: I/O error, dev mtdblock1, sector 8
[  284.776520] blk_update_request: I/O error, dev mtdblock1, sector 16
[  284.783178] blk_update_request: I/O error, dev mtdblock1, sector 24
[  284.789403] blk_update_request: I/O error, dev mtdblock1, sector 0
[  284.793998] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  284.922561] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  284.925548] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  284.932400] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  284.946731] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  284.949258] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  284.956028] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  284.976743] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  337.446175] usb 3-1: USB disconnect, device number 8
[  337.446214] usb 3-1.3: USB disconnect, device number 9
[  337.496251] usb 3-1.4: USB disconnect, device number 10
[  341.364904] usb 3-1: new high-speed USB device number 11 using xhci-hcd
[  341.511437] hub 3-1:1.0: USB hub found
[  341.511765] hub 3-1:1.0: 4 ports detected
[  341.795577] usb 3-1.3: new high-speed USB device number 12 using xhci-hcd
[  341.898483] usb 3-1.3: ep 0x81 - rounding interval to 128 microframes, ep desc says 255 microframes
[  341.898544] usb 3-1.3: ep 0x2 - rounding interval to 128 microframes, ep desc says 255 microframes
[  341.907650] usb-storage 3-1.3:1.0: USB Mass Storage device detected
[  341.918300] scsi host8: usb-storage 3-1.3:1.0
[  342.004684] usb 3-1.4: new high-speed USB device number 13 using xhci-hcd
[  342.801258] usb-storage 3-1.4:1.0: USB Mass Storage device detected
[  342.802075] scsi host9: usb-storage 3-1.4:1.0
[  342.926135] scsi 8:0:0:0: Direct-Access     Kingston DataTraveler G2  1.00 PQ: 0 ANSI: 2
[  342.930991] sd 8:0:0:0: [sda] 31252024 512-byte logical blocks: (16.0 GB/14.9 GiB)
[  342.935368] sd 8:0:0:0: [sda] Write Protect is off
[  342.941962] sd 8:0:0:0: [sda] Mode Sense: 16 24 09 51
[  342.947082] sd 8:0:0:0: [sda] Incomplete mode parameter data
[  342.950821] sd 8:0:0:0: [sda] Assuming drive cache: write through
[  342.961155]  sda: sda1 sda2
[  342.965083] sd 8:0:0:0: [sda] Attached SCSI removable disk
[  343.685152] Adding 1047548k swap on /dev/sda1.  Priority:-1 extents:1 across:1047548k 
[  343.811012] scsi 9:0:0:0: Direct-Access                               1.00 PQ: 0 ANSI: 6
[  343.812183] sd 9:0:0:0: [sdb] 122880000 512-byte logical blocks: (62.9 GB/58.6 GiB)
[  343.824837] sd 9:0:0:0: [sdb] Write Protect is off
[  343.825605] sd 9:0:0:0: [sdb] Mode Sense: 23 00 00 00
[  343.835389] sd 9:0:0:0: [sdb] Write cache: disabled, read cache: disabled, doesn't support DPO or FUA
[  343.838434]  sdb: sdb1
[  343.853513] sd 9:0:0:0: [sdb] Attached SCSI removable disk
[  344.105784] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: 
[  344.872367] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: 
[  350.339502] blk_update_request: 40 callbacks suppressed
[  350.339529] blk_update_request: I/O error, dev mtdblock0, sector 0
[  350.344193] blk_update_request: I/O error, dev mtdblock0, sector 8
[  350.350669] blk_update_request: I/O error, dev mtdblock0, sector 16
[  350.356776] blk_update_request: I/O error, dev mtdblock0, sector 24
[  350.363492] blk_update_request: I/O error, dev mtdblock0, sector 0
[  350.368358] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  350.377892] blk_update_request: I/O error, dev mtdblock1, sector 0
[  350.382984] blk_update_request: I/O error, dev mtdblock1, sector 8
[  350.388977] blk_update_request: I/O error, dev mtdblock1, sector 16
[  350.417413] blk_update_request: I/O error, dev mtdblock1, sector 24
[  350.418083] blk_update_request: I/O error, dev mtdblock1, sector 0
[  350.422481] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  350.560621] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  350.563961] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  350.571980] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  350.586054] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  350.589396] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  350.596084] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  350.617353] Buffer I/O error on dev mtdblock9, logical block 0, async page read
[  458.236354] blk_update_request: 40 callbacks suppressed
[  458.236379] blk_update_request: I/O error, dev mtdblock0, sector 0
[  458.241397] blk_update_request: I/O error, dev mtdblock0, sector 8
[  458.247981] blk_update_request: I/O error, dev mtdblock0, sector 16
[  458.253989] blk_update_request: I/O error, dev mtdblock0, sector 24
[  458.260240] blk_update_request: I/O error, dev mtdblock0, sector 0
[  458.265210] Buffer I/O error on dev mtdblock0, logical block 0, async page read
[  458.274247] blk_update_request: I/O error, dev mtdblock1, sector 0
[  458.279801] blk_update_request: I/O error, dev mtdblock1, sector 8
[  458.286407] blk_update_request: I/O error, dev mtdblock1, sector 16
[  458.291950] blk_update_request: I/O error, dev mtdblock1, sector 24
[  458.298631] blk_update_request: I/O error, dev mtdblock1, sector 0
[  458.303490] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[  458.435105] Buffer I/O error on dev mtdblock2, logical block 0, async page read
[  458.438035] Buffer I/O error on dev mtdblock3, logical block 0, async page read
[  458.445698] Buffer I/O error on dev mtdblock4, logical block 0, async page read
[  458.459632] Buffer I/O error on dev mtdblock5, logical block 3, async page read
[  458.462934] Buffer I/O error on dev mtdblock6, logical block 0, async page read
[  458.469576] Buffer I/O error on dev mtdblock7, logical block 0, async page read
[  458.490980] Buffer I/O error on dev mtdblock9, logical block 0, async page read

My hypothesis, to avoid such error one can use overlay partition. In this case one may stop read/write to NAND after kernel and init is loaded.

So I guess the I/O errors are normal for R7800? This thread didn't really provide a straight answer, but I have the same errors on my R7800 and the same blocks as well.
The router seems to be functioning normally despite the errors.

No idea if they are relay "normal", but I see them on my own R7800 router, too. And it works quite ok.