Hi, On 2019-12-04 20:45:25 +0100, Peter Eisentraut wrote: > In the previous discussions on backtrace support, some people asked for > backtraces in more situations. Here is a patch that prints backtraces on > SIGABRT, SIGBUS, and SIGSEGV signals. SIGABRT includes assertions and > elog(PANIC).
Hm. Can we really do that somewhat reliably like this? I'd suspect that there'll be some oddities e.g. for stack overflows if done this way. To my knowledge it's not a good idea to intercept SIGBUS/SIGSEGV without using a separate signal stack (cf. sigaltstack) - but using a separate stack could also make it harder to determine a correct backtrace? It'd be bad if the addition of backtraces for SEGV/BUS suddenly made it harder to attach a debugger and getting useful results. Even disregarding the previous concerns, we'll get less useful debugger interactions due to this, e.g. for things like null pointer derefs, right? Doing this for SIGABRT seems like a more clearly good case - by that point we're already removed a few frames from the triggering code anyway. So debugging experience won't suffer much. And I don't think there's a corresponding issue with the stack potentially being corrupted / not large enough. - Andres
