iperf3 test causes a panic in linkerd-tcp

[linkerd]

iperf3 test causes a panic in linkerd-tcp

[stevej]

The panic comes from the slice primitive slice, specifically fromclone_from_slice https://github.com/rust-lang/rust/blob/master/src/libcore/slice/mod.rs#L590

This method is called by proxy_stream.rs here: https://github.com/linkerd/linkerd-tcp/blob/master/src/lb/proxy_stream.rs#L134

[stevej]

Some trace log lines right before the panic

^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: poll
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.4:37388))).read(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: read 8192 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::socket      ^[[0m: Socket(Plain(V4(10.240.0.10:7474))).write(8192)
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: wrote 6656 bytes
^[[35mTRACE^[[0m:^[[1mlinkerd_tcp::lb::proxy_stream^[[0m: saving 1536 bytes
thread 'main' panicked at 'destination and source slices have different lengths', /checkout/src/libcore/slice/mod.rs:591
stack backtrace:
   0:     0x5623f50f2e63 - std::sys::imp::backtrace::tracing::imp::unwind_backtrace::h0c49f46a3545f908
                               at /checkout/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1:     0x5623f50eecf4 - std::sys_common::backtrace::_print::hcef39a9816714c4c
                               at /checkout/src/libstd/sys_common/backtrace.rs:71
   2:     0x5623f50f57a7 - std::panicking::default_hook::{{closure}}::h7c3c94835e02f846
                               at /checkout/src/libstd/sys_common/backtrace.rs:60
                               at /checkout/src/libstd/panicking.rs:355
   3:     0x5623f50f532b - std::panicking::default_hook::h0bf7bc3112fb107d
                               at /checkout/src/libstd/panicking.rs:371
   4:     0x5623f50f5c7b - std::panicking::rust_panic_with_hook::ha27630c950090fec
                               at /checkout/src/libstd/panicking.rs:549
   5:     0x5623f50f5b54 - std::panicking::begin_panic::heb97fa3158b71158
                               at /checkout/src/libstd/panicking.rs:511
   6:     0x5623f50f5a89 - std::panicking::begin_panic_fmt::h8144403278d84748
                               at /checkout/src/libstd/panicking.rs:495
   7:     0x5623f50f5a17 - rust_begin_unwind
                               at /checkout/src/libstd/panicking.rs:471
   8:     0x5623f5120efd - core::panicking::panic_fmt::h3b0cca53e68f9654
                               at /checkout/src/libcore/panicking.rs:69
   9:     0x5623f5120e34 - core::panicking::panic::h4b991f5abe7d76d5
                               at /checkout/src/libcore/panicking.rs:49
  10:     0x5623f4faff7c - <linkerd_tcp::lb::proxy_stream::ProxyStream as futures::future::Future>::poll::h16aa78271f3f436f

I think this is an off-by-one error.