assertion failed: task.unwinder.unwinding

[jorendorff]

fatal runtime error: assertion failed: task.unwinder.unwinding
Abort trap: 6

Program here: https://gist.github.com/jorendorff/6380686

Compiled with rustc -o blocking_pipe blocking_pipe.rs

Output here, with a stack: https://gist.github.com/jorendorff/6383398

[jorendorff]

@bblum noted that this doesn't reproduce readily on Linux. I'm on Mac. Maybe changing the 100 on line 100 to a larger number would make it more likely to reproduce, as it would create more tasks (but I'm not too hopeful).

[jorendorff]

A shorter version that also crashes here: https://gist.github.com/jorendorff/6383761

[jorendorff]

It is distinctly more likely with more RUST_THREADS. Try 16.

[bblum]

Changing number of threads or number of iterations does not help. Still haven't been able to reproduce here.

[jorendorff]

OK, one more observation (and I'd be thrilled to gdb this for you, to answer your questions, play your hunches, whatever. I just don't know what to look for.)

There are two ways for the leftover tasks in this program to be killed:

task <unnamed> failed at 'killed by linked failure', /Users/jorendorff/dev/rust/rust/src/libstd/rt/kill.rs:627
task <unnamed> failed at 'receiving on closed channel', /Users/jorendorff/dev/rust/rust/src/libstd/rt/comm.rs:487

The assertion failure only seems to occur when many tasks are "killed by linked failure". When most tasks are killed the other way, it doesn't happen.

[bblum]

It's weird that you say that, because whenever I run the test, basically all the tasks are killed by linked failure. I think I only have one each time receiving on a closed channel.

You say you can gdb it? Can you get a backtrace?

[jorendorff]

@bblum Yes, see the last link in the initial report.