From: Kefu Chai <kchai@redhat.com>
Date: Sun, 20 Sep 2020 03:30:26 +0000 (+0800)
Subject: common/BackTrace: do not use len for length of demangled symbol
X-Git-Tag: v17.0.0~1068^2
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=14b6d35b17b3316eb8d30f009ad18dc793e0929b;p=ceph-ci.git

common/BackTrace: do not use len for length of demangled symbol

it turns out `len` is longer than the length of demangled symbol,
let's rely on the `\0` sentry in the returned char* string instead.

in this change, use `status` to tell if the demangle is successful or
not.

Fixes: https://tracker.ceph.com/issues/47552
Signed-off-by: Kefu Chai <kchai@redhat.com>
---

diff --git a/src/common/BackTrace.cc b/src/common/BackTrace.cc
index 1dfa39cda17..e6396afe3a7 100644
--- a/src/common/BackTrace.cc
+++ b/src/common/BackTrace.cc
@@ -52,10 +52,10 @@ std::string BackTrace::demangle(const char* name)
     // only demangle a C++ mangled name
     if (mangled.compare(0, 2, "_Z") == 0) {
       // let __cxa_demangle do the malloc
-      size_t len = 0;
-      if (char* demangled = abi::__cxa_demangle(mangled.c_str(), nullptr, &len, &status)) {
+      char* demangled = abi::__cxa_demangle(mangled.c_str(), nullptr, nullptr, &status);
+      if (!status) {
         std::string full_name{OPEN};
-        full_name += std::string_view(demangled, len);
+        full_name += demangled;
         full_name += end;
         // buf could be reallocated, so free(demangled) instead
         free(demangled);