diff --git a/SOURCES/gcc8-rh1981822.patch b/SOURCES/gcc8-rh1981822.patch
new file mode 100644
index 0000000..af47325
--- /dev/null
+++ b/SOURCES/gcc8-rh1981822.patch
@@ -0,0 +1,75 @@
+From 55f40d968b0bd3be4478a9481e829a99ee0fa04f Mon Sep 17 00:00:00 2001
+From: Jason Merrill <jason@redhat.com>
+Date: Mon, 5 Apr 2021 22:50:44 -0400
+Subject: [PATCH] c++: mangling of lambdas in default args [PR91241]
+
+In this testcase, the parms remembered in LAMBDA_EXPR_EXTRA_SCOPE are no
+longer the parms of the FUNCTION_DECL they have as their DECL_CONTEXT, so we
+were mangling both lambdas as parm #0.  But since the parms are numbered
+from right to left we don't need to need to find them in the FUNCTION_DECL,
+we can measure their own DECL_CHAIN.
+
+gcc/cp/ChangeLog:
+
+	PR c++/91241
+	* mangle.c (write_compact_number): Add sanity check.
+	(write_local_name): Use list_length for parm number.
+
+gcc/testsuite/ChangeLog:
+
+	PR c++/91241
+	* g++.dg/abi/lambda-defarg1.C: New test.
+---
+ gcc/cp/mangle.c                           | 11 ++---------
+ gcc/testsuite/g++.dg/abi/lambda-defarg1.C | 11 +++++++++++
+ 2 files changed, 13 insertions(+), 9 deletions(-)
+ create mode 100644 gcc/testsuite/g++.dg/abi/lambda-defarg1.C
+
+diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
+index 6c111342b97..4399165ee23 100644
+--- gcc/cp/mangle.c
++++ gcc/cp/mangle.c
+@@ -1628,6 +1628,7 @@ write_literal_operator_name (tree identifier)
+ static void
+ write_compact_number (int num)
+ {
++  gcc_checking_assert (num >= 0);
+   if (num > 0)
+     write_unsigned_number (num - 1);
+   write_char ('_');
+@@ -2027,15 +2028,7 @@ write_local_name (tree function, const tree local_entity,
+   /* For this purpose, parameters are numbered from right-to-left.  */
+   if (parm)
+     {
+-      tree t;
+-      int i = 0;
+-      for (t = DECL_ARGUMENTS (function); t; t = DECL_CHAIN (t))
+-	{
+-	  if (t == parm)
+-	    i = 1;
+-	  else if (i)
+-	    ++i;
+-	}
++      int i = list_length (parm);
+       write_char ('d');
+       write_compact_number (i - 1);
+     }
+diff --git a/gcc/testsuite/g++.dg/abi/lambda-defarg1.C b/gcc/testsuite/g++.dg/abi/lambda-defarg1.C
+new file mode 100644
+index 00000000000..8c538581240
+--- /dev/null
++++ gcc/testsuite/g++.dg/abi/lambda-defarg1.C
+@@ -0,0 +1,11 @@
++// PR c++/91241
++// { dg-do compile { target c++11 } }
++
++struct A {
++  int *b(const int & = []() -> int { return 0; }(),
++	 const int & = []() -> int { return 0; }());
++};
++int *A::b(const int &, const int &) { b(); return 0; }
++// { dg-final { scan-assembler "_ZN1A1bERKiS1_" } }
++// { dg-final { scan-assembler "_ZZN1A1bERKiS1_Ed_NKUlvE_clEv" } }
++// { dg-final { scan-assembler "_ZZN1A1bERKiS1_Ed0_NKUlvE_clEv" } }
+-- 
+2.27.0
diff --git a/SPECS/gcc.spec b/SPECS/gcc.spec
index c56c835..d2627b3 100644
--- a/SPECS/gcc.spec
+++ b/SPECS/gcc.spec
@@ -4,7 +4,7 @@
 %global gcc_major 8
 # Note, gcc_release must be integer, if you want to add suffixes to
 # %%{release}, append them after %%{gcc_release} on Release: line.
-%global gcc_release 2
+%global gcc_release 3
 %global nvptx_tools_gitrev c28050f60193b3b95a18866a96f03334e874e78f
 %global nvptx_newlib_gitrev aadc8eb0ec43b7cd0dd2dfb484bae63c8b05ef24
 %global _unpackaged_files_terminate_build 0
@@ -252,7 +252,10 @@ Obsoletes: libcilkrts-static
 Requires(post): /sbin/install-info
 Requires(preun): /sbin/install-info
 AutoReq: true
+# Various libraries are imported.  #1859893 asks us to list them all.
 Provides: bundled(libiberty)
+Provides: bundled(libbacktrace)
+Provides: bundled(libffi)
 Provides: gcc(major) = %{gcc_major}
 
 Patch0: gcc8-hack.patch
@@ -275,6 +278,7 @@ Patch17: gcc8-libgomp-testsuite.patch
 Patch18: gcc8-remove-old-demangle.patch
 Patch19: gcc8-rh1960701.patch
 Patch20: gcc8-pr100797.patch
+Patch21: gcc8-rh1981822.patch
 
 Patch30: gcc8-rh1668903-1.patch
 Patch31: gcc8-rh1668903-2.patch
@@ -854,6 +858,7 @@ to NVidia PTX capable devices if available.
 %patch18 -p0 -b .demangle~
 %patch19 -p0 -b .rh1960701~
 %patch20 -p0 -b .pr100797~
+%patch21 -p0 -b .rh1981822~
 
 %patch30 -p0 -b .rh1668903-1~
 %patch31 -p0 -b .rh1668903-2~
@@ -3170,6 +3175,10 @@ fi
 %endif
 
 %changelog
+* Tue Jul 13 2021 Marek Polacek <polacek@redhat.com> 8.5.0-3
+- fix mangling of lambdas in default args (PR c++/91241, #1981822)
+- add a few Provides: bundled
+
 * Tue Jun  1 2021 Marek Polacek <polacek@redhat.com> 8.5.0-2
 - revert upstream PR85873 gcc-8 fix, apply the fix from gcc-9 (#1960701)
 - fix 'this' adjustment for devirtualized call (PR c++/100797, #1965951)