From 2c02fe03f3146bd6e976fd28ac0973696a7f804e Mon Sep 17 00:00:00 2001
From: yzewei <141103849+yzewei@users.noreply.github.com>
Date: Mon, 29 Jun 2026 17:48:05 +0800
Subject: [PATCH] gh-152240: Fix test_c_stack_unwind on Linux LoongArch builds
 (GH-152241) (cherry picked from commit
 8458582736b69b1ac05eef65230c4806f92891cd)

Co-authored-by: yzewei <141103849+yzewei@users.noreply.github.com>
---
 .../Build/2026-06-26-16-30-00.gh-issue-152240.loongarch.rst | 2 ++
 Modules/_testinternalcapi.c                                 | 6 ++++++
 2 files changed, 8 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Build/2026-06-26-16-30-00.gh-issue-152240.loongarch.rst

diff --git a/Misc/NEWS.d/next/Build/2026-06-26-16-30-00.gh-issue-152240.loongarch.rst b/Misc/NEWS.d/next/Build/2026-06-26-16-30-00.gh-issue-152240.loongarch.rst
new file mode 100644
index 000000000000000..ce9274a5c108377
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-06-26-16-30-00.gh-issue-152240.loongarch.rst
@@ -0,0 +1,2 @@
+Fix C stack unwinding tests on Linux LoongArch builds by teaching the manual
+frame pointer unwinder to recognize the LoongArch frame layout.
diff --git a/Modules/_testinternalcapi.c b/Modules/_testinternalcapi.c
index 92a49d003ca7359..a96131d1ef4fcc0 100644
--- a/Modules/_testinternalcapi.c
+++ b/Modules/_testinternalcapi.c
@@ -98,6 +98,12 @@ static const uintptr_t min_frame_pointer_addr = 0x1000;
 // https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi-1.9.html#STACK
 #  define FRAME_POINTER_NEXT_OFFSET 0
 #  define FRAME_POINTER_RETURN_OFFSET 2
+#elif defined(__loongarch__)
+// On LoongArch, the frame pointer is the caller's stack pointer.
+// The saved frame pointer is stored at fp[-2], and the return
+// address is stored at fp[-1].
+#  define FRAME_POINTER_NEXT_OFFSET -2
+#  define FRAME_POINTER_RETURN_OFFSET -1
 #else
 #  define FRAME_POINTER_NEXT_OFFSET 0
 #  define FRAME_POINTER_RETURN_OFFSET 1