From 87b4c91813f69f081690461affdf3157d7bb3e71 Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Mon, 8 Jul 2024 08:55:50 +0200
Subject: [PATCH] Dump stack trace on hvc_remove

---
 lagarto-ox.nix | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lagarto-ox.nix b/lagarto-ox.nix
index 0aeb392..37543d2 100644
--- a/lagarto-ox.nix
+++ b/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