diff --git a/libunwind/src/UnwindCursor.hpp b/libunwind/src/UnwindCursor.hpp
--- a/libunwind/src/UnwindCursor.hpp
+++ b/libunwind/src/UnwindCursor.hpp
@@ -32,6 +32,9 @@
 
 #if defined(_LIBUNWIND_TARGET_LINUX) &&                                        \
     (defined(_LIBUNWIND_TARGET_AARCH64) || defined(_LIBUNWIND_TARGET_S390X))
+#include <sys/syscall.h>
+#include <sys/uio.h>
+#include <unistd.h>
 #define _LIBUNWIND_CHECK_LINUX_SIGRETURN
 #endif
 
@@ -2620,16 +2623,28 @@
   //
   // [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/vdso/sigreturn.S
   const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
+  // The PC might contain an invalid address if the unwind info is bad, so
+  // directly accessing it could cause a segfault. Use process_vm_readv to read
+  // the memory safely instead. process_vm_readv was added in Linux 3.2, and
+  // AArch64 supported was added in Linux 3.7, so the syscall is guaranteed to
+  // be present. Unfortunately, there are Linux AArch64 environments where the
+  // libc wrapper for the syscall might not be present (e.g. Android 5), so call
+  // the syscall directly instead.
+  uint32_t instructions[2];
+  struct iovec local_iov = {&instructions, sizeof instructions};
+  struct iovec remote_iov = {reinterpret_cast<void *>(pc), sizeof instructions};
+  long bytesRead =
+      syscall(SYS_process_vm_readv, getpid(), &local_iov, 1, &remote_iov, 1, 0);
   // Look for instructions: mov x8, #0x8b; svc #0x0
-  if (_addressSpace.get32(pc) == 0xd2801168 &&
-      _addressSpace.get32(pc + 4) == 0xd4000001) {
-    _info = {};
-    _info.start_ip = pc;
-    _info.end_ip = pc + 4;
-    _isSigReturn = true;
-    return true;
-  }
-  return false;
+  if (bytesRead != sizeof instructions || instructions[0] != 0xd2801168 ||
+      instructions[1] != 0xd4000001)
+    return false;
+
+  _info = {};
+  _info.start_ip = pc;
+  _info.end_ip = pc + 4;
+  _isSigReturn = true;
+  return true;
 }
 
 template <typename A, typename R>
diff --git a/libunwind/test/bad_unwind_info.pass.cpp b/libunwind/test/bad_unwind_info.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libunwind/test/bad_unwind_info.pass.cpp
@@ -0,0 +1,73 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Ensure that libunwind doesn't crash on invalid info; the Linux aarch64
+// sigreturn frame check would previously attempt to access invalid memory in
+// this scenario.
+// REQUIRES: linux && (target={{aarch64-.+}} || target={{x86_64-.+}})
+
+// TODO: Figure out why this fails with Memory Sanitizer.
+// XFAIL: msan
+
+#undef NDEBUG
+#include <assert.h>
+#include <libunwind.h>
+#include <stdio.h>
+
+#if defined(__x86_64__)
+__asm__(".globl bad_unwind_info\n"
+        "bad_unwind_info:\n"
+        "        .cfi_startproc\n"
+        "        pushq   %rbx\n"
+        "        .cfi_def_cfa_offset 16\n"
+        "        movq    8(%rsp), %rbx\n"
+        "        # purposely corrupt return value on stack\n"
+        "        movq    $4, 8(%rsp)\n"
+        "        callq   stepper\n"
+        "        movq    %rbx, 8(%rsp)\n"
+        "        popq    %rbx\n"
+        "        .cfi_def_cfa_offset 8\n"
+        "        ret\n"
+        "        .cfi_endproc\n");
+#elif defined(__aarch64__)
+__asm__(".globl bad_unwind_info\n"
+        "bad_unwind_info:\n"
+        "        .cfi_startproc\n"
+        "        // not using 0 because unwinder was already resilient to it\n"
+        "        mov     x8, #4\n"
+        "        stp     x30, x8, [sp, #-16]!\n"
+        "        .cfi_def_cfa_offset 16\n"
+        "        // purposely use incorrect offset for x30\n"
+        "        .cfi_offset x30, -8\n"
+        "        bl      stepper\n"
+        "        ldr     x30, [sp], #16\n"
+        "        .cfi_def_cfa_offset 0\n"
+        "        .cfi_restore x30\n"
+        "        ret\n"
+        "        .cfi_endproc\n");
+#else
+#error "This test is only supported for aarch64 or x86-64"
+#endif
+
+extern "C" {
+void stepper() {
+  unw_cursor_t cursor;
+  unw_context_t uc;
+  unw_getcontext(&uc);
+  unw_init_local(&cursor, &uc);
+  // stepping to bad_unwind_info should succeed
+  assert(unw_step(&cursor) > 0);
+  // stepping past bad_unwind_info should fail but not crash
+  assert(unw_step(&cursor) <= 0);
+}
+
+void bad_unwind_info();
+}
+
+int main() { bad_unwind_info(); }