As per
google/oss-fuzz#5442

Some Go fuzzer programs (configured with whatever oss-fuzz does to combine Go with the address sanitizer) are crashing with:

Crash Type: Null-dereference READ
Crash Address: 0x000000000000
Crash State:
pthread_create
_cgo_try_pthread_create
pthread_create

The actual Go code under test does not spawn its own goroutines, although it does involve asm code which IIUC is similar to cgo:
https://github.com/google/oss-fuzz/blob/master/projects/go-snappy/fuzz.go
https://github.com/golang/snappy/blob/master/decode.go
https://github.com/golang/snappy/blob/master/decode_amd64.s

Another comment in that 5442 issue says:

This bug happens for every golang project since go 1.16
I think it happened as well in go 1.15 but only for fuzz targets running multiple goroutines

So perhaps the asm thing is unrelated??

Any suggestions on what to try next?

Also posted to https://groups.google.com/g/golang-dev/c/3DrZWztdaX0 but there's not much discussion there.