From d5e4a13128d47e852b47a1b4c86c1a97bbd7da4c Mon Sep 17 00:00:00 2001
From: Alexey Sheplyakov <asheplyakov@basealt.ru>
Date: Thu, 20 Jul 2023 08:56:17 +0400
Subject: [PATCH 1/2] LoongArch: rtld: avoid segfaults when tracing

cat > test.c <<EOF
struct THD;
extern __thread struct THD *current_thd;
void *test() { return current_thd; }
EOF

gcc -ftls-model=initial-exec -shared -fPIC -o libtest.so test.c
env LD_TRACE_LOADED_OBJECTS=1 LD_WARN=1 LD_BIND_NOW=1 /lib64/ld-linux-loongarch-lp64d.so.1 ./libtest.so
    statically linked
undefined symbol: current_thd   (./libtest.so)
Segmentation fault

This failure is particularly annoying since the above tracing command
is used when building RPM packages.

This patch adds missing checks for NULL in LoongArch specific
elf_machine_rela function to avoid the problem.
---
 sysdeps/loongarch/dl-machine.h | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/sysdeps/loongarch/dl-machine.h b/sysdeps/loongarch/dl-machine.h
index 1e07d124f9..0bd158f0af 100644
--- a/sysdeps/loongarch/dl-machine.h
+++ b/sysdeps/loongarch/dl-machine.h
@@ -175,16 +175,21 @@ elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
 
 #ifndef RTLD_BOOTSTRAP
     case __WORDSIZE == 64 ? R_LARCH_TLS_DTPMOD64 : R_LARCH_TLS_DTPMOD32:
-      *addr_field = sym_map->l_tls_modid;
+      if (sym_map)
+        *addr_field = sym_map->l_tls_modid;
       break;
 
     case __WORDSIZE == 64 ? R_LARCH_TLS_DTPREL64 : R_LARCH_TLS_DTPREL32:
-      *addr_field = TLS_DTPREL_VALUE (sym) + reloc->r_addend;
+      if (sym != NULL)
+        *addr_field = TLS_DTPREL_VALUE (sym) + reloc->r_addend;
       break;
 
     case __WORDSIZE == 64 ? R_LARCH_TLS_TPREL64 : R_LARCH_TLS_TPREL32:
-      CHECK_STATIC_TLS (map, sym_map);
-      *addr_field = TLS_TPREL_VALUE (sym_map, sym) + reloc->r_addend;
+      if (sym != NULL && sym_map != NULL)
+	{
+	  CHECK_STATIC_TLS (map, sym_map);
+	  *addr_field = TLS_TPREL_VALUE (sym_map, sym) + reloc->r_addend;
+	}
       break;
 
     case R_LARCH_COPY:
-- 
2.33.8