Fix hang on SIGINT when I/O pipes are broken#595
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d-e-s-o wants to merge 1 commit intocontainers:mainfrom
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Fix hang on SIGINT when I/O pipes are broken#595d-e-s-o wants to merge 1 commit intocontainers:mainfrom
d-e-s-o wants to merge 1 commit intocontainers:mainfrom
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Fix two bugs that cause the host process to hang at 100% CPU when SIGINT is delivered while the I/O pipes are broken (e.g., when the parent process dies after Ctrl+C). The hang has two contributing factors: 1. The TX thread spins when a pipe breaks. write_desc_to_output returns Err(BrokenPipe), but the error arm only logs and continues the loop. After the loop, bytes_written == 0 causes undo_pop, and pop_head_blocking immediately returns the same descriptor, creating a tight spin. Fix this by returning from process_tx on write error. 2. The RX pop_head_blocking never checks the stop flag. Port::shutdown sets stop=true and unparks the RX thread, but the thread parks again without checking stop, so join hangs forever. Fix this by checking the stop flag after signal_used_queue in the None branch and returning None to the caller. Signed-off-by: Daniel Müller <deso@posteo.net>
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I did verify that I was no longer reproduce the hangs/stray threads with the fix. Also, 60c6756 contains a vibe-coded test that Claude assures me reproduces the issue. I did verify it failed before and succeeds now, but haven't looked at it closely otherwise, as I am not sure we want to land it. |
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Fix two bugs that cause the host process to hang at 100% CPU when SIGINT is delivered while the I/O pipes are broken (e.g., when the parent process dies after Ctrl+C).
The hang has three contributing factors: