https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120834
Bug ID: 120834
Summary: Potential memory leak during exception handling
Product: gcc
Version: 15.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dorian.haglund at gmail dot com
Target Milestone: ---
Running the following code with valgrind reports an error:
```cpp
struct throwing_dtor_t {
~throwing_dtor_t() noexcept(false) { throw 123; }
};
int main() {
try {
try {
throw throwing_dtor_t{};
} catch (throwing_dtor_t const &) {
}
} catch (int) {
}
return 0;
}
```
```bash
~ $ 0 valgrind --leak-check=full ./a.out
==143975== Memcheck, a memory error detector
==143975== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==143975== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info
==143975== Command: ./a.out
==143975==
==143975==
==143975== HEAP SUMMARY:
==143975== in use at exit: 129 bytes in 1 blocks
==143975== total heap usage: 3 allocs, 2 frees, 73,989 bytes allocated
==143975==
==143975== 129 bytes in 1 blocks are definitely lost in loss record 1 of 1
==143975== at 0x4846828: malloc (in
/usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==143975== by 0x492CD4B: __cxa_allocate_exception (in
/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.33)
==143975== by 0x1091DE: main (in /home/dorian/a.out)
==143975==
==143975== LEAK SUMMARY:
==143975== definitely lost: 129 bytes in 1 blocks
==143975== indirectly lost: 0 bytes in 0 blocks
==143975== possibly lost: 0 bytes in 0 blocks
==143975== still reachable: 0 bytes in 0 blocks
==143975== suppressed: 0 bytes in 0 blocks
==143975==
==143975== For lists of detected and suppressed errors, rerun with: -s
==143975== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
```
A leak also appear if you turn both asan and ubsan on (but not only asan)
System:
```bash
~ $ 0 uname -a
Linux dorian-XPS-15-9510 6.11.0-26-generic #26~24.04.1-Ubuntu SMP
PREEMPT_DYNAMIC Thu Apr 17 19:20:47 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
```
