[BUG] dm-crypt broken after 2632e2521769 ("arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD")

[Johannes Nixdorf]

On 2024-05-16 17:22, Johannes Nixdorf wrote:
> I noticed frequent FS corruption on my M1 MacBook running Linux after
> the Asahi Linux Kernel was updated to 6.9.x (from 6.6.x).

A small correction: I noticed it at the jump to 6.8.x. The bisect started
with 6.8.9 as the first bad commit.

To make sure I now tested it again with the current master at ea5f6ad9ad96. The
bug still reproduces with it.

> This was reproduced with fio's examples/basic-verify.fio (1GB of writing
> was not reliably, 10GB triggered it reliably) on vanilla kernels and
> happens on any storage backend behind dm-crypt.

I reproduced it with the following script in the initramfs since I did not
have a working keyboard with vanilla kernels:

 fallocate -l $((1024 * 1024 * 1024)) disk.img
 losetup -f disk.img
 echo test | cryptsetup luksFormat -q /dev/loop0
 echo test | cryptsetup open /dev/loop0 test
 fio /verify.fio

And the following verify.fio:

 [write-and-verify]
 loops=10
 rw=randwrite
 bs=4k
 direct=1
 ioengine=libaio
 iodepth=16
 verify=crc32c
 filename=/dev/mapper/test

Regards,
Johannes Nixdorf