asio event loop stuck infinitly when signal(SIGABRT, SEGV,...) is raised while executing another task about asio

[GowrishankarSG05]

I just dug into the code around boost asio and noticed the root cause of this issue.

Steps to create this issue:

1. Register for system signal(SIGSEGV, SIGABRT, ...) using signal_set
2. Run the event loop using io_service::run(). io_service here it has only one job that is to monitor watch signals.
3. Now post a job to io_service
4. While the job is being executed, Deliberately make SIGSEGV by simple accessing nullptr ;)
5. This is the starting point where event loop start to stuck in an infinite loop

Order of the execution:

1. When SIGSEGV is raised while executing a job, the program execution moves to boost_asio_signal_handler
2. boost_asio_signal_handler simple writes into a fd which is what being monitored in the other side, I assume.
3. Then hereafter boost_asio_signal_handler just leaves the function
4. Now the execution control moves to the place where SIGSEGV risen.
5. In this use case, Sadly epoll_wait will never have a chance to notify about the data written by boost_asio_signal_handler.
6. Step 1 to 5 repeats infinitely.