The most obvious effect is that crtl-c doesn't work anymore or sometimes a program can't terminate itself. All the children of the affected process inherit the broken sigprocmask. In my case, I noticed when I couldn't unlock gnome-screensaver anymore. A strace showed that it sent itself SIGTERM after getting the correct password but didn't receive it. Further digging led to this bugreport: https://devtalk.nvidia.com/default/topic/638521/linux/gnome-terminal-problems-ctrl-c-and-exit/ Downgrading to 325.15 fixed the issue. I chose "severity: major" because when the windowmanager is affected, major breakage occurs without the reason being obvious.
*** This bug has been marked as a duplicate of bug 487558 ***
