Dump stack trace on hvc_remove

lagarto-ox.nix

@@ -93,6 +93,17 @@
       ''
         echo 0 > /proc/sys/vm/compaction_proactiveness
       ''
+      +
+      # Show stacktrace on calls to the hvc_remove function.
+      ''
+        echo "Mount debugfs"
+        mkdir -p /sys/kernel/debug/
+        mount -t debugfs none /sys/kernel/debug/
+        td=/sys/kernel/debug/tracing
+        echo hvc_remove > $td/set_ftrace_filter
+        echo function > $td/current_tracer
+        echo 1 > $td/options/func_stack_trace
+      ''
 #      FIXME: Disable sched_switch for now, as it still hangs the boot...
 #      +
 #      # Exclude the second pid, which is the kthread that will dump the trace to