diff --git a/gnu/local.mk b/gnu/local.mk
index 357ec3b7f2..746f5c5779 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -855,6 +855,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/clang-runtime-asan-build-fixes.patch	\
   %D%/packages/patches/clang-runtime-esan-build-fixes.patch	\
   %D%/packages/patches/clang-runtime-9-libsanitizer-mode-field.patch	\
+  %D%/packages/patches/clang-runtime-3.5-libsanitizer-mode-field.patch	\
   %D%/packages/patches/clang-runtime-3.9-libsanitizer-mode-field.patch	\
   %D%/packages/patches/clang-runtime-3.8-libsanitizer-mode-field.patch	\
   %D%/packages/patches/classpath-aarch64-support.patch		\
diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index af1fb6cf7f..15078a1168 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -781,6 +781,7 @@ components which highly leverage existing libraries in the larger LLVM Project."
                   llvm-3.5
                   "1hsdnzzdr5kglz6fnv3lcsjs222zjsy14y8ax9dy6zqysanplbal"
                   '("clang-runtime-asan-build-fixes.patch"
+                    "clang-runtime-3.5-libsanitizer-mode-field.patch"
                     "clang-3.5-libsanitizer-ustat-fix.patch"))))
     (package
       (inherit runtime)
diff --git a/gnu/packages/patches/clang-runtime-3.5-libsanitizer-mode-field.patch b/gnu/packages/patches/clang-runtime-3.5-libsanitizer-mode-field.patch
new file mode 100644
index 0000000000..9e9d57d265
--- /dev/null
+++ b/gnu/packages/patches/clang-runtime-3.5-libsanitizer-mode-field.patch
@@ -0,0 +1,29 @@
+Adjust libsanitizer to ABI change in glibc 2.31.
+
+Adapted to 3.x from this upstream commit:
+https://github.com/llvm/llvm-project/commit/947f9692440836dcb8d88b74b69dd379d85974ce
+
+--- a/lib/sanitizer_common/saniniitizer_platform_limits_posix.h.orig	2020-08-11 16:01:32.494882282 +0200 #
++++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.h	2020-08-11 16:32:49.711383554 +0200
+@@ -176,8 +176,7 @@
+     unsigned long __unused1;
+     unsigned long __unused2;
+ #else
+-    unsigned short mode;
+-    unsigned short __pad1;
++    unsigned int mode;
+     unsigned short __seq;
+     unsigned short __pad2;
+ #if defined(__x86_64__) && !defined(_LP64)
+--- a/lib/sanitizer_common/sanitizer_platform_limits_posix.cc	2020-08-11 16:01:07.926821829 +0200
++++ b/lib/sanitizer_common/sanitizer_platform_limits_posix.cc.orig	2020-08-11 16:01:03.698811421 +0200
+@@ -1056,7 +1056,9 @@
+ CHECK_SIZE_AND_OFFSET(ipc_perm, gid);
+ CHECK_SIZE_AND_OFFSET(ipc_perm, cuid);
+ CHECK_SIZE_AND_OFFSET(ipc_perm, cgid);
++#if !SANITIZER_LINUX || __GLIBC_PREREQ (2, 31)
+ CHECK_SIZE_AND_OFFSET(ipc_perm, mode);
++#endif
+ 
+ CHECK_TYPE_SIZE(shmid_ds);
+ CHECK_SIZE_AND_OFFSET(shmid_ds, shm_perm);