[tigran]

Thank you very much for the explanation.

Here is something curious you might find interesting. The number of "plug" processes grows with each USB plugin (as storage), see:

844 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
847 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
854 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1005 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1008 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1015 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1211 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1214 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1221 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1382 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1385 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1392 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1531 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1534 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1542 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1644 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug
1647 root 0:00 {plug} /bin/sh /usr/local/Kobo/udev/plug

Now I rebooted the device and logged in again via usbnet and there are no "plug" processes.

Do you think KSM is responsible for this? It is under its control that usb storage plug in is done...

Also, an unrelated question: do you know if "factory reset" actually reformats the vfat data partition or do I need to do it manually? (i.e. if it simply removes all the files in it, then it won't be enough to clear my fs corruption).