Under 2.6.33-rcX (at least rc5 and rc6, didn't check earlier versions), I started seeing these messages in dmesg (I do not see these messages on 2.6.32): [ 16.528951] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda9 [ 16.529570] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda9 [ 16.553175] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda7 [ 16.553846] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda7 [ 16.577349] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda6 [ 16.577954] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda6 [ 16.684570] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda5 [ 16.695916] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda5 [ 16.702729] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda2 [ 16.702743] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda2 [ 16.747168] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9c4) on /dev/sda1 [ 16.747786] ioctl32(mdadm:2243): Unknown cmd fd(3) cmd(800c0910){t:09;sz:12} arg(ffb7f9e4) on /dev/sda1 I am running 32 bit userspace on 64 bit kernel. I do not observe any ill effects, possibly because I do not really use raid. The command in question seems to be RAID_VERSION. I have verified that reverting aa98aa31987ad9831711ae71ea2270228ab62532 makes the errors go away. Didn't yet bother opening a bugzilla for this, let me know if I should. -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html