Re: sparc64 mystery with Cheetah+ D-cache parity error (n_tty_set_termios, bpf_check, cheetah_copy_page_insn)

From: Meelis Roos <redacted>
Date: Wed, 10 Oct 2018 16:24:59 +0300

I have seen multiple strange messages like this, on multiple sparc64
machines:

[ 55.523882] CPU[1]: Cheetah+ D-cache parity error at
TPC[0000000000707e8c]
[   55.626033] TPC<n_tty_set_termios+0x2c/0x3c0>

This specfic one ise from n_tty_set_termios and it is currently
repeatable on a Sun V210.
I have seen these on V245 and V445 too, with different addresses. On
V445, the same address caused
errors on multiple CPUs so it does not seem like a hardware problem,
rather something software releated,
that's why I am reporting it here.

On V445 it is gone with my current custom kernels but was there with
4.16.0-1-sparc64-smp Debian kernel package,
probabaly because I do not have bpfilter compiled in:

I just started getting my older machines up again and I get these
kinds of errors sometimes too, usually in the TSB copy routine.

I'll definitely be looking into this and thanks for the report and
data.