fix process-panic-after-fork on some Linux

[llogiq]

On an old voidlinux system I tested, the final status.signal() is Some(libc::SIGIOT), which fails the test. So I just extend the assertion to cover this case.

[rustbot]

r? @wesleywiser

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[bjorn3]

Which kernel version is that?

[llogiq]

@bjorn3

$ uname -a
Linux 6.18.34_1 #1 SMP PREEMPT_DYNAMIC Mon Jun  1 22:43:42 UTC 2026 x86_64 GNU/Linux

[bjorn3]

On Linux SIGIOT seems to be an alias for SIGABRT. At least to me that seems like the test genuinely failed as it didn't reach the explicit SIGUSR1 raise.

[llogiq]

In that case, what can I do to help debug the issue?

[bjorn3]

Maybe try running the test in gdb with set detach-on-fork off and then check where the SIGIOT/SIGABRT happens?