[Bug 218601] Regression - dd if=/dev/zero of=/zero causes shift-out-of-bounds && NULL pointer dereference, address: 0000000000000003

bugzilla-daemon
2024-03-19T06:22:42Z

--- Comment #6 from Colin (colin.kernel@i-pentest.info) ---
Firstly, apologies for any incorrectness - the commit reference link did not
accept inputs that were 'probably this sha' or similar - it was not meant in
malice or laziness, but admittedly I was very tiered as a result of the
unpredictability of this issue.

I suspect this may actually be dead hardware but it's hard to tell. If somebody
is interested in exploring this issue further feel free to provide instruction
over the next few days, otherwise I'll buy a new motherboard / RMA the
processor if the motherboard does not fix the issue. I value both my and all of
your time, so buying new equipment in the hopes that I'm rid of the problem is
my preference unless there's some burning desire for further exploration.

Here are some facts:

- `stress-ng --class cpu --seq 32` reliably crashes the machine in less than 60
seconds with the error message 'stress-ng: fail: [2701] af-alg: ctr(twofish):
decrypted data different from original data (possible kernel bug)', as well as
other algos (pcbc(fcrypt), cbc(sm4) etc) noting `dd if=/dev/zero` is not
cryptographic. I routinely checksum files with sha and do not notice any
inconsistencies.
- I have tried vanilla kernels inc. 6.0.1 and 6.8, `dd` _seems_ to fail faster
with more recent kernels, but maybe that's just due to a small test sample
size.
- I have been unable to crash Windows using Prime95 (24h) Furmark (24h) nor dd,
nor am I aware of any errors from either tool. Windows install routinely BSOD,
but went away as soon as I switched to a different USB stick both freshly
flashed - it's possible this is related, but it could also be a bad USB.
- The motherboard is an ASUS Prime Z790-P WiFi D4 LGA 1700, the processor a
13900k, I have been experiencing the issue for about 12 months, seemingly it
has become more frequent lately
- I cannot visually see any problems with the motherboard, no bloated
capacitors as far as I can tell.
- I have replaced the RAM, PSU, SSDs (w/ an non-samsung model) and removed all
aux cards, with the exception of onboard wifi6 which cannot be removed
- Memtest86+ was run with my original 128G ram configuration on 2x24h occasions
and did not yield any errors indicating cpu<>memory integrity is not the issue