Re: Can't umount /mnt/dev after calling dd(1) and with /mnt/dev is a bind mount

From: Al Viro
Date: Sat Mar 22 2014 - 15:24:37 EST

On Sat, Mar 22, 2014 at 05:52:24PM +0100, Francis Moreau wrote:
> I'm posting here because it might be a behaviour related to the kernel
> internals that I can't explain from my user point of view :)
> Basically I'm doing this:
> mount -o bind /dev/ /mnt/dev &&
> chroot /mnt dd bs=440 conv=notrunc count=1 if=gptmbr.bin of=/dev/loop0
> umount /mnt/dev
> but umount gives the following error: "umount: /mnt/dev: target is busy"

What do you have in /proc/self/mountinfo before all that?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at