4.16. bash

When a SIGCHLD signal was received in job control mode and a handler for the signal was installed, Bash called the trap handler within the signal handler itself. This was unsafe and could cause Bash to enter a deadlock or to terminate unexpectedly with a segmentation fault due to memory corruption. With this update, the trap handler is now called outside of the signal handler, and Bash no longer enters a deadlock, neither crashes in this scenario.