`sockets_0_3_udp_sample_application` fails intermittently

[dicej]

I've seen this twice now on CI; rerunning the job usually fixes it (but apparently erases the log of the failure, alas). Here's the error:

failures:

---- p3::sockets::sockets_0_3_udp_sample_application stdout ----
Error: guest trapped

Caused by:
    0: error while executing at wasm backtrace:
           0: 0x5082 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN107_$LT$test_programs..p3..wasi..sockets..types..UdpSocket$u20$as$u20$test_programs..p3.._rt..WasmResource$GT$4drop17h25938a5a6606521aE
           1: 0xbc44 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN83_$LT$test_programs..p3.._rt..Resource$LT$T$GT$$u20$as$u20$core..ops..drop..Drop$GT$4drop17h3aca6384ac18e51dE
           2: 0xbbbf - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN4core3ptr111drop_in_place$LT$test_programs..p3.._rt..Resource$LT$test_programs..p3..wasi..sockets..types..UdpSocket$GT$$GT$17h6d5022325a368400E
           3: 0xbd91 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN4core3ptr71drop_in_place$LT$test_programs..p3..wasi..sockets..types..UdpSocket$GT$17hd2997f8a01f07d7aE
           4: 0x2548 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN34sockets_0_3_udp_sample_application27test_udp_sample_application28_$u7b$$u7b$closure$u7d$$u7d$28_$u7b$$u7b$closure$u7d$$u7d$17haae37bcd63304885E
           5: 0x1e05 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN103_$LT$futures_util..future..maybe_done..MaybeDone$LT$Fut$GT$$u20$as$u20$core..future..future..Future$GT$4poll17h614bae705140a9fdE
           6: 0xd766 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN34sockets_0_3_udp_sample_application27test_udp_sample_application28_$u7b$$u7b$closure$u7d$$u7d$28_$u7b$$u7b$closure$u7d$$u7d$17h2170046e12f60b2bE
           7: 0xd6e7 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN95_$LT$futures_util..future..poll_fn..PollFn$LT$F$GT$$u20$as$u20$core..future..future..Future$GT$4poll17ha257113536c8ba5aE
           8: 0xee84 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN34sockets_0_3_udp_sample_application27test_udp_sample_application28_$u7b$$u7b$closure$u7d$$u7d$17h6950fdf7e0e239deE
           9: 0xaa40 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN115_$LT$sockets_0_3_udp_sample_application..Component$u20$as$u20$test_programs..p3..exports..wasi..cli..run..Guest$GT$3run28_$u7b$$u7b$closure$u7d$$u7d$17h20758710e99b3af8E
          10: 0x1a06 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN13test_programs2p37exports4wasi3cli3run16_export_run_cabi28_$u7b$$u7b$closure$u7d$$u7d$17hc0f6cd6314eafaefE
          11: 0x16cd - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN102_$LT$futures_util..future..future..map..Map$LT$Fut$C$F$GT$$u20$as$u20$core..future..future..Future$GT$4poll17hfa2387c3405f8b0cE
          12: 0xdc4c - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN97_$LT$futures_util..future..future..Map$LT$Fut$C$F$GT$$u20$as$u20$core..future..future..Future$GT$4poll17h4915eb8dee47d561E
          13: 0x261ea - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN72_$LT$core..pin..Pin$LT$P$GT$$u20$as$u20$core..future..future..Future$GT$4poll17h5c2a9c81795a46f4E
          14: 0x25b52 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN117_$LT$futures_util..stream..futures_unordered..FuturesUnordered$LT$Fut$GT$$u20$as$u20$futures_core..stream..Stream$GT$9poll_next17he7e4ab41a664b882E
          15: 0x26e90 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN12futures_util6stream6stream9StreamExt15poll_next_unpin17hfe93f109423484cdE
          16: 0x242bd - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN14wit_bindgen_rt13async_support4poll17h4fbbdbc9d8fefd42E
          17: 0x24728 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN14wit_bindgen_rt13async_support8callback17h3635ebb41cbd4b10E
          18: 0xf870 - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm!_ZN13test_programs2p37exports4wasi3cli3run14__callback_run17h000903064a9bfc9bE
          19: 0xf04f - sockets_0_3_udp_sample_application-c39a2b4e75374b15.wasm![callback][async]wasi:cli/run@0.3.0#run
       note: using the `WASMTIME_BACKTRACE_DETAILS=1` environment variable may show more debugging information
    1: cannot remove owned resource while borrowed


failures:
    p3::sockets::sockets_0_3_udp_sample_application

test result: FAILED. 209 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 99.63s

error: test failed, to rerun pass `-p wasmtime-wasi --test all`

[dicej]

@rvolosatovs FYI

[rvolosatovs]

Interesting, thanks for the report! Feel free to ignore it for now, I'll debug tomorrow

[dicej]

@alexcrichton It just occurred to me that this could be an example of the drop-future-that-has-a-resource-borrow issue you brought up today. The test uses the join! macro to poll two futures concurrently, and if one of them fails the other will be dropped, which I think will cascade to dropping the resource.

I'm becoming more and more convinced that we need task cancellation after all.

[dicej]

BTW, I suspect the root cause of this test failure is not the "cannot remove owned resource while borrowed" trap; I'm guessing something's going wrong before that, but the trap sure doesn't help us diagnose the root cause.