Kernel-4.14: With ubuntu-18.04 building rootfs images and booting gives SQUASHFS error: xz decompression failed, data probably corrupt

[Pintu Agarwal]

On Tue, 9 Nov 2021 at 16:45, Pintu Agarwal <pintu.ping at gmail.com> wrote:
>
> Hi,
>
> On Mon, 8 Nov 2021 at 20:00, Pintu Agarwal <pintu.ping at gmail.com> wrote:
> >
> > Hi,
> > Here are few details.
> > * Linux Kernel: 4.14
> > * Processor: Qualcomm Arm32 Cortex-A7
> > * Storage: NAND 512MB
> > * Platform: Simple busybox
> > * Filesystem: UBIFS, Squashfs
> > * Build system: Linux Ubuntu 18.04 with Yocto build system
> > * Consists of nand raw partitions, squashfs ubi volumes.
> >
> > What we are trying to do:
> > We are trying to boot dm-verity enabled rootfs on our system.
> > The images for rootfs were generated on Ubuntu 18.04 machine using
> > Yocto build system.
> >
> > Issue:
> > Earlier, when we were using Ubuntu 16.04 to generate our images, the
> > system was booting fine even with dm-verity enabled.
> > Recently we switched to Ubuntu 18.04 build machine, and now with the
> > same changes we are seeing the below squashfs error, just after the
> > mount.
> > Note: with 18.04 also our rootfs is mounting successfully and
> > dm-verity is also working fine.
> > We only get these squashfs errors flooded in the boot logs:
> > {{{
> > ....
> > [    5.153479] device-mapper: init: dm-0 is ready
> > [    5.334282] VFS: Mounted root (squashfs filesystem) readonly on device 253:0.
> > ....
> > [    8.954120] SQUASHFS error: xz decompression failed, data probably corrupt
> > [    8.954153] SQUASHFS error: squashfs_read_data failed to read block 0x1106
> > [    8.970316] SQUASHFS error: Unable to read data cache entry [1106]
> > [    8.970349] SQUASHFS error: Unable to read page, block 1106, size 776c
> > [    8.980298] SQUASHFS error: Unable to read data cache entry [1106]
> > [    8.981911] SQUASHFS error: Unable to read page, block 1106, size 776c
> > [    8.988280] SQUASHFS error: Unable to read data cache entry [1106]
> > ....
> > }}}
> >
> Just one question:
> Is there any history about these squashfs errors while cross-compiling
> images on Ubuntu 18.04 or higher ?
>
One quick observation:
This issue is seen only when we enable dm-verity in our bootloader and
cross-building the bootloader/kernel (with Yocto 2.6 toolchain
arm-oe-linux-gnueabi-) on Ubuntu 18.04.
The issue is *NOT* seen (on the same device) when building the
dm-verity enabled kernel on Ubuntu 16.04.

Is it something to do with the cross-toolchain difference between
Ubuntu 16 and 18 ?


Thanks,
Pintu