Potential null pointer dereference

[Wiktor-99]

Required information

Operating system:
Ubuntu 20.04/22.04/24.04 LTS

Compiler version:
GCC 14.2.0

Eclipse iceoryx version:
v2.0.6

Observed result or behaviour:
While compiling with -O2 flag following warnings are seen:

In constructor ‘iox::cxx::error<T>::error(Targs&& ...) [with Targs = {iox::popo::AllocationError&}; T = iox::popo::AllocationError]’,
63.43     inlined from ‘iox::cxx::expected<void*, iox::popo::AllocationError> iox::popo::UntypedPublisherImpl<BasePublisherType>::loan(uint32_t, uint32_t, uint32_t, uint32_t) [with BasePublisherType = iox::popo::BasePublisher<>]’ at /usr/local/include/iceoryx/v2.0.6/iceoryx_posh/internal/popo/untyped_publisher_impl.inl:51:21,
63.43 /usr/local/include/iceoryx/v2.0.6/iceoryx_hoofs/internal/cxx/expected.inl:72:7: error: potential null pointer dereference [-Werror=null-dereference]
63.43    72 |     : value(std::forward<Targs>(args)...)
63.43       |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
63.43 In file included from /usr/local/include/iceoryx/v2.0.6/iceoryx_posh/internal/popo/untyped_publisher_impl.hpp:79:
63.43 In member function ‘iox::cxx::expected<void*, iox::popo::AllocationError> iox::popo::UntypedPublisherImpl<BasePublisherType>::loan(uint32_t, uint32_t, uint32_t, uint32_t) [with BasePublisherType = iox::popo::BasePublisher<>]’,
63.43 /usr/local/include/iceoryx/v2.0.6/iceoryx_posh/internal/popo/untyped_publisher_impl.inl:55:63: error: potential null pointer dereference [-Werror=null-dereference]
63.43    55 |         return cxx::success<void*>(result.value()->userPayload());

Expected result or behaviour:
What do you expect to happen?
No warnings.

Conditions where it occurred / Performed steps:
Compile with gcc-14.2.0 and -O2 flag

[elBoberido]

@Wiktor-99 I tried to reproduce the issue with gcc-14.2.1 on Arch Linux but was not able to get those warnings.

I also looked at the code in untyped_publisher_impl.inl:55 and I think it is a false positive. Are you able to update to 14.2.1 and check if the warning is still present on your setup?

[Wiktor-99]

I'll try it out with gcc-14.2.1 and let you know.

[elBoberido]

@Wiktor-99 can you confirm that the issue is fixed with gcc-14.2.1?

[Wiktor-99]

No, it's still visible. I tested it against 15.1.0 (c++23).
The issue is visible while I include given header in my app:

#include <iceoryx_posh/popo/untyped_subscriber.hpp>

[elBoberido]

I just tried it but could also not reproduce the issue. We have multiple examples which include that header and they compile fine. I even tried an out-of-tree build with those examples.

There are some warnings like -Wstringop-overflow and -Warray-bounds but those are false positives and suppressed on main.

Do you have the same issue on main?

Can you give a step by step description how you trigger this warning? We are using the expected also for the C++ bindings of iceoryx2 and I want to ensure it is indeed a false positive.

[Wiktor-99]

I managed to extract a minimal example that reproduces the error.
You can check it out here: https://github.com/Wiktor-99/iceroyx-reproduction. I believe you only need to have Docker installed to run it. It wasn't visible without -O2 flag.