These failures started within the 1.18 cycle, so marking as release-blocker to determine whether this is a regression (and whether it may affect other platforms too).

These failures look weird, especially being nondeterministic. Maybe it is due to memory corruption somewhere?

Not really sure what to do with this bug, given the failure mode. Normally I would lease a builder and run some test or set of tests in a loop to try to reproduce -- in this case, even if I were able to reproduce it a few times, what then? I don't see any commonality in terms of the symbols that are suddenly being switched from reachable to unreachable.

Maybe it is due to memory corruption somewhere?

“possible memory corruption on FreeBSD” is #46272, open since May. 😩

Still, it seems odd to me that this particular failure mode doesn't show up in the logs until recently. Maybe the memory corruption has a non-trivial interaction with the 1.18 GC changes? (Perhaps the corruption is triggered by having the GC active during some step of the linking process?)

Just out of curiosity, how far back does "greplogs" go? What's the oldest log that it will fetch?

Depends on what you've downloaded with fetchlogs. (It looks like the semi-arbitrary cutoff for my database for the main repo is currently 2019-06-06.)

Checking on this as a release blocker. Are there any updates? @thanm

Still look like memory corruption. Seems no new failure occurred since 11-22. Haven't tried to reproduce.

I kicked off a goswarm on freebsd-amd64-12_2 this morning trying to reproduce the issue. I'll leave it running for a day or two and see if that catches any new instances of the bug. I tried to do something similar for an AMD-specific VM (e.g. netbsd-amd64-9_0-n2d) but all.bash crashes almost immediately there (most of the time doesn't make it past the bootstrap).

OK, it took a while, but the swarm I started this morning did find a new instance of this problem on tip with freebsd-amd64-12_2 just now, so it definitely looks like this bug is alive and kicking.

Related: #46272 (comment). I will retest this bug once we have an updated version of FreeBsd on our builders with the fix.

I ran a goswarm test (using the updated freebsd-amd64-13_0 builder image to include the fix) and did not detect any new failures over the course of a 40 hour run with 10 gomotes, so I am going to go ahead and close out this bug. See #46272 for more details on the kernel problem and the fix.