vm/qemu, vm/gce: dump LOCKDEP state in Diagnose

For context see the discussion at:
https://groups.google.com/g/syzkaller/c/ruwaYUvwHTw/m/E9Cg9OfvAgAJ

1 files changed, 26 insertions, 0 deletions

diff --git a/vm/vmimpl/linux.go b/vm/vmimpl/linux.go
new file mode 100644
index 000000000..0406035f6
--- /dev/null
+++ b/vm/vmimpl/linux.go
@@ -0,0 +1,26 @@
+// Copyright 2020 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package vmimpl
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/google/syzkaller/pkg/report"
+)
+
+// DiagnoseLinux diagnoses some Linux kernel bugs over the provided ssh callback.
+func DiagnoseLinux(rep *report.Report, ssh func(args ...string) ([]byte, error)) (output []byte, wait, handled bool) {
+	if !strings.Contains(rep.Title, "MAX_LOCKDEP") {
+		return nil, false, false
+	}
+	// Dump /proc/lockdep* files on BUG: MAX_LOCKDEP_{KEYS,ENTRIES,CHAINS,CHAIN_HLOCKS} too low!
+	output, err := ssh("cat", "/proc/lockdep_stats", "/proc/lockdep", "/proc/lockdep_chains")
+	if err != nil {
+		output = append(output, err.Error()...)
+	}
+	// Remove mangled pointer values, they take lots of space but don't add any value.
+	output = regexp.MustCompile(` *\[?[0-9a-f]{8,}\]?\s*`).ReplaceAll(output, nil)
+	return output, false, true
+}