Bug#752603: linux-image-3.14-0.bpo.1-amd64: mising xz BJC filters cause squashfs read errors
Package: src:linux
Version: 3.14.7-1~bpo70+1
Severity: normal
Greetings, Thanks for the back port kernels!
In a recent kernel version (3.14?) the xz compression BCJ filters became
optional. 3.14-0.bpo.1-amd64 only has the X86 filter included (see config
except below). Unfortunately this causes squashfs to fail in a misleading
manner when a file is read from a squashfs filesystem that uses a filter
not compiled into the kernel (see the -Xbcj flag to mksquashfs). When
decompression of such a file occurs the error produced suggests that the
squashfs filesystem is corrupt which, at least in my case, it is not
(see dmesg excerpt below). This makes files in filesystems that use
these filters (eg: filesystem images of embedded systems) unreadable.
The misleading error message has been discussed (eg:
https://lkml.org/lkml/2014/3/5/132) so forwarding this upstream is
unneeded.
If all the BCJ filters could be enabled (as they were before the option
to disable them appeared) it would be much appreciated. I for one have
a fair number of squashfs filesystems that use foreign architecture
filters and unsquashfs'ing them instead of just mounting them reduces
the utility of squashfs.
Thanks!
P.S. I've reduced the info below as this is a known issue and not related
to the system these logs were taken on. I also booted to a shell as init
to reduce the noise. If you feel that other information is relevant I
can provide it.
Here are the applicable kernel options:
grep _XZ_ /boot/config-3.14-0.bpo.1-amd64:
CONFIG_XZ_DEC=y
CONFIG_XZ_DEC_X86=y
# CONFIG_XZ_DEC_POWERPC is not set
# CONFIG_XZ_DEC_IA64 is not set
# CONFIG_XZ_DEC_ARM is not set
# CONFIG_XZ_DEC_ARMTHUMB is not set
# CONFIG_XZ_DEC_SPARC is not set
CONFIG_XZ_DEC_BCJ=y
# CONFIG_XZ_DEC_TEST is not set
-- Package-specific info:
** Version:
Linux version 3.14-0.bpo.1-amd64 (debian-kernel@lists.debian.org) (gcc version 4.6.3 (Debian 4.6.3-14) ) #1 SMP Debian 3.14.7-1~bpo70+1 (2014-06-21)
** Command line:
BOOT_IMAGE=/vmlinuz-3.14-0.bpo.1-amd64 root=/dev/mapper/vg0-root ro init=/bin/bash
** Not tainted
** Kernel log:
..snip..
[ 145.928009] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 155.419853] SQUASHFS error: xz decompression failed, data probably corrupt
[ 155.421981] SQUASHFS error: squashfs_read_data failed to read block 0x3116
[ 155.424105] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.426239] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.428408] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.430134] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.431860] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.433573] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.435296] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.437020] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.438764] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.440231] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.441691] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.443157] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.444617] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.446068] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.447533] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.448999] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.450472] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.451940] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.453416] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.454847] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.456118] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.457387] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.458668] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.459948] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.461232] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.462525] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.463807] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.465077] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.466343] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.467544] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.468655] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.469757] SQUASHFS error: Unable to read page, block 3116, size 7578
[ 155.470864] SQUASHFS error: Unable to read data cache entry [3116]
[ 155.471960] SQUASHFS error: Unable to read page, block 3116, size 7578
** Loaded modules:
squashfs
loop
nls_utf8
nls_cp437
vfat
fat
ext4
crc16
mbcache
jbd2
btrfs
xor
raid6_pq
sha256_ssse3
sha256_generic
usb_storage
hid_apple
hid_generic
usbhid
hid
dm_crypt
dm_mod
md_mod
sg
sd_mod
crc_t10dif
crct10dif_pclmul
crct10dif_common
crc32_pclmul
crc32c_intel
ahci
ghash_clmulni_intel
libahci
libata
xhci_hcd
aesni_intel
aes_x86_64
lrw
gf128mul
glue_helper
ablk_helper
cryptd
scsi_mod
usbcore
usb_common
-- System Information:
Debian Release: 7.5
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 3.14-0.bpo.1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ISO-8859-1)
Shell: /bin/sh linked to /bin/dash
Versions of packages linux-image-3.14-0.bpo.1-amd64 depends on:
ii debconf [debconf-2.0] 1.5.49
ii initramfs-tools [linux-initramfs-tool] 0.115~bpo70+1
ii kmod 9-3
ii linux-base 3.5
ii module-init-tools 9-3
Versions of packages linux-image-3.14-0.bpo.1-amd64 recommends:
ii firmware-linux-free 3.2
Versions of packages linux-image-3.14-0.bpo.1-amd64 suggests:
pn debian-kernel-handbook <none>
pn grub-pc | extlinux | lilo <none>
pn linux-doc-3.14 <none>
Versions of packages linux-image-3.14-0.bpo.1-amd64 is related to:
pn firmware-atheros <none>
pn firmware-bnx2 <none>
pn firmware-bnx2x <none>
pn firmware-brcm80211 <none>
pn firmware-intelwimax <none>
pn firmware-ipw2x00 <none>
pn firmware-ivtv <none>
pn firmware-iwlwifi <none>
pn firmware-libertas <none>
ii firmware-linux 0.41~bpo70+1
ii firmware-linux-nonfree 0.41~bpo70+1
pn firmware-myricom <none>
pn firmware-netxen <none>
pn firmware-qlogic <none>
pn firmware-ralink <none>
pn firmware-realtek <none>
pn xen-hypervisor <none>
-- debconf information:
linux-image-3.14-0.bpo.1-amd64/prerm/removing-running-kernel-3.14-0.bpo.1-amd64: true
linux-image-3.14-0.bpo.1-amd64/postinst/depmod-error-initrd-3.14-0.bpo.1-amd64: false
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