[LEDE-DEV] Update to util-linux 2.30.1 breaks x86_64 squashfs-combined

[Daniel Golle]

On Fri, Sep 29, 2017 at 12:20:08PM +0200, Felix Fietkau wrote:
> On 2017-09-11 02:33, Philip Prindeville wrote:
> > Changing the subject from the previous thread as it turned out to not have to do with sysupgrade at all.
> > 
> > What I can tell is this, having added some tracing to fstools.
> > 
> > We get to the call to system() in rootdisk_volume_init():
> > 
> > https://git.lede-project.org/?p=project/fstools.git;a=blob;f=libfstools/rootdisk.c;h=dd00c1b4e5b4aa9b748610fa3e93d301a67101a7;hb=HEAD#l269
> > 
> > and it never seems to return.  The value of “str” is “mkfs.f2fs -q -l rootfs_data /dev/loop0”.
> > 
> > What would cause this to hang rather than return an error?
> I've used sysrq to trace this and found out that it's hanging in the
> getrandom system call, which could be used through util-linux library
> code. That also explains why the update broke it.
> 
> I will prepare a patch that forces util-linux to stick to /dev/urandom
> instead - that should hopefully fix this for good.

mkfs.f2fs also uses getrandom(3) and hangs there for some minutes when
creating the initial snapshot...