Mount FreeBSD UFS from logical partition under Linux

How can I mount the FreeBSD UFS boot partition under Ubuntu in this setup: - a single HDD which contains - an MBR partition table which contains - some primary Linux partitions and an extended partition which contains - a Linux logical partition and a FreeBSD logical partition which contains - the FreeBSD disklabel (so the logical partition is the "slice") which contains - the FreeBSD boot (UFS) and swap partitions Here is the MBR partitioning: ubuntu$ sudo fdisk -l /dev/sda Disk /dev/sda: 42.9 GB, 42949672960 bytes 255 heads, 63 sectors/track, 5221 cylinders, total 83886080 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0005d5af Device Boot Start End Blocks Id System /dev/sda1 * 2048 1953791 975872 83 Linux /dev/sda2 1953792 11718655 4882432 83 Linux /dev/sda3 11718656 13672447 976896 82 Linux swap / Solaris /dev/sda4 13674494 83884031 35104769 5 Extended /dev/sda5 13674496 33204223 9764864 83 Linux /dev/sda6 33206272 83884031 25338880 a5 FreeBSD And here is the disklabel: freebsd$ disklabel /dev/ada0s6 # /dev/ada0s6: 8 partitions: # size offset fstype [fsize bsize bps/cpg] a: 48580592 16 4.2BSD 0 0 0 b: 2097152 48580608 swap c: 50677760 0 unused 0 0 # "raw" part, don't edit I can boot FreeBSD using the following /etc/grub.d/40_custom: #!/bin/sh exec tail -n +3 $0 # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. menuentry "FreeBSD" { insmod part_bsd insmod ufs2 set root="(hd0,msdos6,bsd1)" kfreebsd /boot/kernel/kernel set kFreeBSD.acpi_load=YES set kFreeBSD.hint.acpi.0.disabled=0 set kFreeBSD.vfs.root.mountfrom=ufs:/dev/ada0s6a kfreebsd_loadenv /boot/device.hints } That way I can access the FreeBSD partition from grub2 with no problems. But Linux does not detect any BSD partitions: ubuntu$ ls /dev/sda* /dev/sda /dev/sda1 /dev/sda2 /dev/sda3 /dev/sda4 /dev/sda5 /dev/sda6 Versions: Ubuntu 14.04 with kernel 4.2.0-27-generic on x86_64, FreeBSD 10.3 RELEASE amd64, both fresh installs.