Change https://golang.org/cl/353355 mentions this issue: testing: write output to buffer when fuzzing

Change https://golang.org/cl/355691 mentions this issue: internal/fuzz: fix bugs with minimization

I'm going to re-open this and have it track non-recoverable crashes that occur during minimization of interesting inputs.

Like @jayconrod says in #48163

#48731 is my main concern. We need to be able to reconstruct the entry that caused a problem, whether we're fuzzing or minimizing. Writing the entry to shared memory before every call to the fuzz target is too expensive because of the marshaling overhead, so we need to be able to rebuilt it from the input entry and some known sequence of transformations. For minimization, I think we should store the sequence of transformations in shared memory. For normal fuzzing, we already store initial RNG state and a count, and that works well enough. In any case, we do still need shared memory, but we could use a lot less of it since we don't need to store inputs there.

The beta is getting close and this is currently marked as blocking the beta. Any news here?

Yes I've been working on this for the past few days. I expect to send a patch next week, and will get it reviewed quickly.

If it ends up getting too close to the beta and we can't get the full fix in, I have a workaround that we can do which is a fairly small change. Will re-assess next week.

The beta won't come out until December 15 at the earliest, due to the 2 week delay, correct? Just want to make sure I understand the timeline correctly.

(For the fuzzing team - the smaller change would be to just fail minimization and use the initial input instead if a non-recoverable error occurs during minimization. This is especially fine if the reason we're minimizing is b/c we found a recoverable error. It's less great if it was during minimization of an interesting input, since that would bury a crash. But it would probably be reasonable for 1.18)

We're trying to get the beta done in early December -- if it's ready on Dec 1, we'll ship it then, if it's not ready until the 15th that's okay too. Earlier is better if convenient.

Change https://golang.org/cl/367848 mentions this issue: internal/fuzz: handle unrecoverable errors during minimization