Michael Pratt

[2022-08-08T14:10:19-964f0c7/linux-amd64-alpine](https://build.golang.org/log/4dcf1b5d8aca26d1053ec7e1b2b31929983aa011)

Since the 10th, when https://go.dev/cl/422097 was submitted. (I'm almost certain the coordinator has been redeployed since then). [2022-08-16T20:39:44-e49e876/linux-amd64-alpine](https://build.golang.org/log/1a14f8aa6120e8855cd5a6ad6191ad2f368e717c) [2022-08-12T16:38:52-f001df5/linux-amd64-alpine](https://build.golang.org/log/3a7f35e212a142683e4b47517de27171930a7c03) [2022-08-12T01:51:51-449691b/linux-amd64-alpine](https://build.golang.org/log/3375bf46b0b8419262c2e5e2cae93f7c857350d3) (Edit: rereading the CL, I see it wasn't intended to...

This is reproducible with `go test` in `misc/cgo/test`. Specifically, on a `linux-amd64-alpine` gomote, I had success with: ``` $ for i in $(seq 1 100); do gomote run -dir ./go/misc/cgo/test...

Elsewhere, @cherrymui mentioned that this looks like it could be corruption from a stack overflow. I agree. In the partial trace below, everything below `0xc000122770` looks like the Go text...

FWIW, I've been unable to reproduce this with `_StackLimit` increased by 10x, which seems consistent with a stack overflow somewhere.

I take that back. It look about an hour (instead of the usual ~5 minutes), but I did get a repro with `10 * _StackLimit`.

I've been making slow progress on this. The most notable is that this reproduces when running only TestSetgid and TestSetgidStress, while it does not reproduce while running only various other...

It looks like the problem is that signal 34 (SIGRT_2) used by musl for setgid is not getting `SA_ONSTACK` set. If I'm interpreting strace correctly, it looks like this signal...

musl does not install the `SIGRT_2` handler until the first call to [`__synccall`](https://git.musl-libc.org/cgit/musl/tree/src/thread/synccall.c#n76) (actually, it reinstalls it on every call), which is why we don't know to add `SA_ONSTACK` at...

Correct, they don't even try to match the existing flags or forward to an existing handler, so we can't install a dummy SA_ONSTACK handler. > Does it mean that they...