From 944d37a96fbb4504b94e76c46a3cd6ad543ca367 Mon Sep 17 00:00:00 2001
From: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com>
Date: Mon, 11 Oct 2021 11:44:42 +0530
Subject: [PATCH] Check tracing dir and add alternate if usual debugfs one
 isn't mounted

---
 kernel/kprobe | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/kprobe b/kernel/kprobe
index b4523d8..fb5035d 100755
--- a/kernel/kprobe
+++ b/kernel/kprobe
@@ -194,6 +194,21 @@ if (( debug )); then
 	echo "kname: $kname, kprobe: $kprobe"
 fi
 
+# It's possible - esp on a production kernel - that CONFIG_DEBUG_FS_DISALLOW_MOUNT=y
+# which implies that though the debugfs filesystem's APIs are available, the
+# fs itself isn't mounted - it's invisible. Take this into account, else the script
+# won't work on such systems
+if [ ! -d ${tracing} ]; then
+   if [ -d /sys/kernel/tracing ]; then
+      tracing=/sys/kernel/tracing
+   else
+      die "ISSUE: neither the /sys/kernel/debug/tracing nor /sys/kernel/tracing dir is available"
+   fi  
+fi
+if (( debug )); then
+    echo "tracing dir: ${tracing}"
+fi
+
 ### check permissions
 cd $tracing || die "ERROR: accessing tracing. Root user? Kernel has FTRACE?
     debugfs mounted? (mount -t debugfs debugfs /sys/kernel/debug)"