lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 3 Apr 2014 13:57:44 -0400
From:	Dave Reisner <>
Subject: Initramfs FSID altered in 3.14


[This is a repost of a G+ post at Tejun's request]

With Linux 3.14, you might notice in /proc/self/mountinfo that your
root's parent FSID is now 0, instead of the 1 that it's been for the
last N years. Tejun wrote the change (9e30cc9595303b27b48) that caused
this, but the change comes in a rather innocuous way. Instead of an
internal kernel mount of sysfs being assigned 0, it's now the initramfs.

So far, this has already caused switch_root and findmnt (from
util-linux) to break, cp (from coreutils) to break when using the -x
flag in early userspace, and it's also been pointed out that systemd's
readahead code makes assumptions about a device number of 0.

Are we now supposed to go and change all the assumptions in userspace
about 0 being special? I'm conflicted. The kernel isn't supposed to
break userspace, but it seems to me that FSIDs were never something to
rely on -- similar to the block device numbering scheme.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists