From 38a2ffe0c733bf0d1d272ed39f54cb6821707c4d Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Tue, 28 Oct 2025 14:13:10 -0700
Subject: [PATCH] Add stacktrace kernelcompat

Signed-off-by: Zach Brown <zab@versity.com>
---
 kmod/src/Makefile.kernelcompat |  8 ++++++++
 kmod/src/kernelcompat.h        | 26 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/kmod/src/Makefile.kernelcompat b/kmod/src/Makefile.kernelcompat
index 3bf3ccdb..47aaf813 100644
--- a/kmod/src/Makefile.kernelcompat
+++ b/kmod/src/Makefile.kernelcompat
@@ -462,3 +462,11 @@ ifneq (,$(shell grep 'struct list_lru_one \*list, spinlock_t \*lock, void \*cb_a
 ccflags-y += -DKC_LIST_LRU_WALK_CB_LIST_LOCK
 endif
 
+#
+# v5.1-rc4-273-ge9b98e162aa5
+#
+# introduce stack trace helpers
+#
+ifneq (,$(shell grep '^unsigned int stack_trace_save' include/linux/stacktrace.h))
+ccflags-y += -DKC_STACK_TRACE_SAVE
+endif
diff --git a/kmod/src/kernelcompat.h b/kmod/src/kernelcompat.h
index 7fb566b5..43e8c91c 100644
--- a/kmod/src/kernelcompat.h
+++ b/kmod/src/kernelcompat.h
@@ -457,4 +457,30 @@ static inline void list_lru_isolate_move(struct list_lru_one *list, struct list_
 }
 #endif
 
+#ifndef KC_STACK_TRACE_SAVE
+#include <linux/stacktrace.h>
+static inline unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+					    unsigned int skipnr)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+                .skip           = skipnr,
+        };
+
+        save_stack_trace(&trace);
+        return trace.nr_entries;
+}
+
+static inline void stack_trace_print(unsigned long *entries, unsigned int nr_entries, int spaces)
+{
+        struct stack_trace trace = {
+                .entries        = entries,
+                .nr_entries     = nr_entries,
+        };
+
+	print_stack_trace(&trace, spaces);
+}
+#endif
+
 #endif