backupccl: panic in backup resumer #52279
Description
I'm on 66a3c19, and I've just started a local node and running the kv workload against it. Within a few minutes I see a panic:
* ERROR: [n1] a panic has occurred!
* runtime error: invalid memory address or nil pointer dereference
* (1) attached stack trace
* | runtime.gopanic
* | /usr/local/Cellar/go/1.14/libexec/src/runtime/panic.go:967
* | runtime.panicmem
* | /usr/local/Cellar/go/1.14/libexec/src/runtime/panic.go:212
* | runtime.sigpanic
* | /usr/local/Cellar/go/1.14/libexec/src/runtime/signal_unix.go:687
* | github.com/cockroachdb/cockroach/pkg/storage/cloudimpl.newResumingHTTPReader
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/storage/cloudimpl/http_storage.go:149
* | github.com/cockroachdb/cockroach/pkg/storage/cloudimpl.(*httpStorage).ReadFile
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/storage/cloudimpl/http_storage.go:254
* | github.com/cockroachdb/cockroach/pkg/ccl/backupccl.readBackupManifest
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/ccl/backupccl/manifest_handling.go:155
* | github.com/cockroachdb/cockroach/pkg/ccl/backupccl.(*backupResumer).Resume
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/ccl/backupccl/backup_job.go:450
* | github.com/cockroachdb/cockroach/pkg/jobs.(*Registry).stepThroughStateMachine
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/jobs/registry.go:850
* | github.com/cockroachdb/cockroach/pkg/jobs.(*Registry).resume.func1
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/jobs/registry.go:986
* | github.com/cockroachdb/cockroach/pkg/util/stop.(*Stopper).RunAsyncTask.func1
* | /Users/rohany/go/src/github.com/cockroachdb/cockroach/pkg/util/stop/stopper.go:347
* | runtime.goexit
* | /usr/local/Cellar/go/1.14/libexec/src/runtime/asm_amd64.s:1373
* Wraps: (2) runtime error: invalid memory address or nil pointer dereference
* Error types: (1) *withstack.withStack (2) runtime.errorString