On 2019-01-23, Ludovic Courtès wrote: > Vagrant Cascadian <[email protected]> skribis: >> After upgrading to linux-libre 4.20, and again tested with 4.20.3, an >> aarch64 system failed to boot (using 4.19.10 worked fine): >> >> [ 3.692351] device-mapper: ioctl: 4.39.0-ioctl (2018-04-03) initialised: >> [email protected] >> ext2fs_check_if_mount: Can't check if filesystem is mounted due to missing >> mtab file while determining whether /dev/sda6 is mounted. >> /dev/sda6: clean, 596262/6553600 files, 7663147/26214400 blocks >> [ 3.948786] EXT4-fs (sda6): Cannot load crc32c driver. >> ERROR: In procedure mount: >> In procedure mount: No such file or directory ... >> Workaround or fix was to add to config.scm: >> >> (initrd (append (list "crc32c_generic" ... ) %base-initrd-modules)) > > There are potentially two issues here: > > 1. Why wasn’t crc32c_generic.ko automatically pulled in by the initrd > build code? Isn’t it a dependency of ext4.ko?
It is not a hard dependency, no. It's an optional feature only needed if
certain ext4 features are enabled on the filesystem (maybe metadata_csum
in this case?). So it's listed as a MODULE_SOFTDEP of ext4:
fs/ext4/super.c:MODULE_SOFTDEP("pre: crc32c");
> 2. Is crc32c_generic built-in in our x86_64 kernel config?
On x86_64:
$ grep CRC32 /gnu/store/*linux-libre*4.20.4*/.config
CONFIG_CRYPTO_CRC32C=y
CONFIG_CRYPTO_CRC32C_INTEL=y
CONFIG_CRYPTO_CRC32=m
CONFIG_CRYPTO_CRC32_PCLMUL=m
CONFIG_CRC32=y
# CONFIG_CRC32_SELFTEST is not set
CONFIG_CRC32_SLICEBY8=y
# CONFIG_CRC32_SLICEBY4 is not set
# CONFIG_CRC32_SARWATE is not set
# CONFIG_CRC32_BIT is not set
CONFIG_LIBCRC32C=m
On aarch64:
$ grep CRC32 /gnu/store/*linux-libre*4.20.3*/.config
CONFIG_CRYPTO_CRC32C=m
CONFIG_CRYPTO_CRC32=m
CONFIG_CRC32=y
# CONFIG_CRC32_SELFTEST is not set
CONFIG_CRC32_SLICEBY8=y
# CONFIG_CRC32_SLICEBY4 is not set
# CONFIG_CRC32_SARWATE is not set
# CONFIG_CRC32_BIT is not set
CONFIG_LIBCRC32C=m
on aarch64 4.19.10 also contained:
CONFIG_CRYPTO_CRC32_ARM64_CE=y
Which is no longer available in 4.20.x upstream in commit
598b7d41e544322c8c4f3737ee8ddf905a44175e.
So my hunch is that crc32c-ce was used in 4.19.x, but 4.20.x needed the
generic crc32c implementation.
live well,
vagrant
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