grub-probe attempts reading irrelevant data many, many times

[Jerzy Tarasiuk]

Hello,
I am just attempting Linux (Ubuntu 16.04) installation
on a disk which has few bad sectors. Before installing
I arranged partitions on the disk in a way that these bad
sectors are in inter-partition space to avoid using it.

When it came to grub installation, one of these bad
sectors was attempted to read - this produced errors.
From syslogs and strace I saw it is grub-probe which
does it - it opens /dev/sda, seeks sector 8954944,
attempts to read 56 sectors, gets 48 of them, attempts
to read 8 more, gets I/O error, closes it, then opens
/dev/sda3, issues fstat(), ioctl(BLKGETSIZE64),
ioctl(BLKSSZGET), lseek(512,SEEK_SET), read(512),
closes, then again opens /dev/sda, and so on, many times
- so the grub installation lasts over 22 hours already.
The /dev/sda3 starts at /dev/sda sector 8955000 - so
the grub-probe attempts to read 56 sectors just preceding
the partition. The Linux is being installed on /dev/sda6;
both /dev/sda3 and /dev/sda6 have ext4 filesystem.
The only partition marked as active is /dev/sda1.

Jerzy Tarasiuk