sql: v23.1.1: nil pointer in getContentionEventInfo

[cockroach-teamcity]

This issue was autofiled by Sentry. It represents a crash or reported error on a live cluster with telemetry enabled.

Sentry link: https://cockroach-labs.sentry.io/issues/4231557744/?referrer=webhooks_plugin

Panic message:

panic.go:884: runtime error: invalid memory address or nil pointer dereference
(1) attached stack trace
-- stack trace:
| runtime.gopanic
| GOROOT/src/runtime/panic.go:884
| runtime.panicmem
| GOROOT/src/runtime/panic.go:260
| runtime.sigpanic
| GOROOT/src/runtime/signal_unix.go:835
| github.com/cockroachdb/cockroach/pkg/sql.getContentionEventInfo
| github.com/cockroachdb/cockroach/pkg/sql/crdb_internal.go:7895
| github.com/cockroachdb/cockroach/pkg/sql.glob..func97.1
| github.com/cockroachdb/cockroach/pkg/sql/crdb_internal.go:7041
| github.com/cockroachdb/cockroach/pkg/sql.setupGenerator.func3
| github.com/cockroachdb/cockroach/pkg/sql/virtual_table.go:127
| github.com/cockroachdb/cockroach/pkg/util/stop.(*Stopper).RunAsyncTaskEx.func2
| github.com/cockroachdb/cockroach/pkg/util/stop/stopper.go:470
| runtime.goexit
| GOROOT/src/runtime/asm_amd64.s:1594
Wraps: (2) runtime error: invalid memory address or nil pointer dereference
Error types: (1) *withstack.withStack (2) runtime.errorString
-- report composition:
runtime.errorString
panic.go:884: *withstack.withStack (top exception)

Stacktrace (expand for inline code snippets):

GOROOT/src/runtime/panic.go#L883-L885 in runtime.gopanic
GOROOT/src/runtime/panic.go#L259-L261 in runtime.panicmem
GOROOT/src/runtime/signal_unix.go#L834-L836 in runtime.sigpanic

cockroach/pkg/sql/crdb_internal.go

Lines 7894 to 7896 in 00f65ea

	if dbDesc != nil {
	schName = schemaDesc.GetName()
	}

in pkg/sql.getContentionEventInfo

cockroach/pkg/sql/crdb_internal.go

Lines 7040 to 7042 in 00f65ea

	// https://github.com/cockroachdb/cockroach/issues/101826
	schemaName, dbName, tableName, indexName, err := getContentionEventInfo(ctx, p, resp.Events[i])
	if err != nil {

in pkg/sql.glob..func97.1

cockroach/pkg/sql/virtual_table.go

Lines 126 to 128 in 00f65ea

	}
	err := worker(ctx, funcRowPusher(addRow))
	// Notify that we are done sending rows.

in pkg/sql.setupGenerator.func3

cockroach/pkg/util/stop/stopper.go

Lines 469 to 471 in 00f65ea

	sp.UpdateGoroutineIDToCurrent()
	f(ctx)
	}()

in pkg/util/stop.(*Stopper).RunAsyncTaskEx.func2
GOROOT/src/runtime/asm_amd64.s#L1593-L1595 in runtime.goexit

GOROOT/src/runtime/panic.go in runtime.gopanic at line 884
GOROOT/src/runtime/panic.go in runtime.panicmem at line 260
GOROOT/src/runtime/signal_unix.go in runtime.sigpanic at line 835
pkg/sql/crdb_internal.go in pkg/sql.getContentionEventInfo at line 7895
pkg/sql/crdb_internal.go in pkg/sql.glob..func97.1 at line 7041
pkg/sql/virtual_table.go in pkg/sql.setupGenerator.func3 at line 127
pkg/util/stop/stopper.go in pkg/util/stop.(*Stopper).RunAsyncTaskEx.func2 at line 470
GOROOT/src/runtime/asm_amd64.s in runtime.goexit at line 1594

Tag	Value
Cockroach Release	v23.1.1
Cockroach SHA:	00f65ea
Platform	linux amd64
Distribution	CCL
Environment	v23.1.1
Command	server
Go Version	``
# of CPUs
# of Goroutines

Jira issue: CRDB-28514

[yuzefovich]

We're incorrectly checking dbDesc and not schemaDesc for non-nil.