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0 pointsPhilipRoman2y ago0 comments

>There is very little you can safely do in a signal handler

You can actually do pretty much anything you want, it's just the C library that uses a lot of global state and internal memory allocations, which messes things up. The core syscall API and any reentrant code you write yourself are not affected.

>The memory state that a program receiving a SIGSEGV in is often undefined/garbage

That may be true for arbitrary segfaults caused by bugs, but the JIT has 100% control over what instructions to emit, it is not restricted by ABIs or platform-specific issues, so there is no problem to use SEGV as a signaling mechanism.

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zozbot2342y ago

You can "do pretty much anything you want" as long as you carefully avoid doing anything non thread-safe (even indirectly) in both the main app and the handler itself? How reassuring!

dwattttt2y ago

The HotSpot JVM is already multithreaded, they understand how to write thread-safe code (I'm not sure which JVM(s?) are reported to be impacted, HotSpot was the first I found a result for).

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