cmd.exe on tmux on WSL freezed

[aont]

Issue Reproduction

cmd.exe on tmux on WSL gets freezed.

I open a tmux session, where cmd.exe is running.

>wsl
$ tmux
$ cmd.exe
>
Ctrl+B D to detach
$ exit

Next, I reopen tmux.

>wsl
$ tmux a
>

I see the previous cmd.exe terminal.
But, any input to cmd.exe is ignored ( though input to tmux is valid for example Ctrl+B & to kill ) .
If this is a bug of tmux, then please let me know. I will post this issue on tmux repos.

Windows: Windows 10 Home 1903 18362.418
Linux: https://lxrunoffline.apphb.com/download/Ubuntu/bionic
tmux: 2.6-3ubuntu0.2

[aont]

Following is the strace output of cmd.exe.

Before exiting WSL

execve("/mnt/c/Windows/system32/cmd.exe", ["cmd.exe"], 0x7fffd991ba88 /* 18 vars */) = 0
arch_prctl(ARCH_SET_FS, 0x293820)       = 0
set_tid_address(0x293858)               = 78
brk(NULL)                               = 0x1cb6000
brk(0x1cb7000)                          = 0x1cb7000
sched_getaffinity(0, 128, [0, 1, 2, 3]) = 64
uname({sysname="Linux", nodename="DESKTOP-IIUBDHU", ...}) = 0
getpid()                                = 78
getcwd("/mnt/c/Users/aont/strace", 4096) = 26
open("/dev/lxss", O_RDWR)               = 3
ioctl(3, _IOC(0, 0, 0x2f, 0x22), 0x7fffddd2ac28) = 0
getcwd("/mnt/c/Users/aont/strace", 4096) = 26
open("/proc/self/mountinfo", O_RDONLY)  = 5
readv(5, [{iov_base="", iov_len=0}, {iov_base="2 2 0:2 / / rw,noatime - wslfs r"..., iov_len=1024}], 2) = 867
readv(5, [{iov_base="", iov_len=0}, {iov_base="", iov_len=1024}], 2) = 0
close(5)                                = 0
getcwd("/mnt/c/Users/aont/strace", 4096) = 26
open("/proc/self/mountinfo", O_RDONLY)  = 5
readv(5, [{iov_base="", iov_len=0}, {iov_base="2 2 0:2 / / rw,noatime - wslfs r"..., iov_len=1024}], 2) = 867
readv(5, [{iov_base="", iov_len=0}, {iov_base="", iov_len=1024}], 2) = 0
close(5)                                = 0
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, TIOCGPGRP, [76])               = 0
getpgid(0)                              = 76
fstat(0, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
fstat(2, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
ioctl(0, TIOCGWINSZ, {ws_row=43, ws_col=168, ws_xpixel=0, ws_ypixel=0}) = 0
ioctl(0, SNDCTL_TMR_START or TCSETS, {B38400 -opost -isig -icanon -echo ...}) = 0
dup(0)                                  = 5
ioctl(4, _IOC(0, 0, 0xb7, 0x22), 0x7fffddd2abd8) = 0
ioctl(4, _IOC(0, 0, 0xb7, 0x22), 0x7fffddd2abd8) = 0
ioctl(4, _IOC(0, 0, 0xb7, 0x22), 0x7fffddd2abd8) = 0
write(4, "\0\0\0\0\260\0\0\0005\1\0\0\0\0\0\0006\1\0\0\0\0\0\0007\1\0\0\0\0\0\0"..., 176) = 176
close(0)                                = 0
close(1)                                = 0
close(2)                                = 0
rt_sigprocmask(SIG_BLOCK, [INT WINCH], NULL, 8) = 0
signalfd4(-1, [INT WINCH], 8, 0)        = 0
poll([{fd=4, events=POLLIN}, {fd=0, events=POLLIN}], 2, -1) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\10\0\0\0 \0\0\0\0\0\0\0\0\0\0\0008\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 32) = 32
ioctl(4, _IOC(0, 0, 0xa3, 0x22), 0x7fffddd2abf8) = 0
poll([{fd=4, events=POLLIN}, {fd=0, events=POLLIN}], 2, -1) = 1 ([{fd=4, revents=POLLHUP}])

After exiting WSL

poll([{fd=4, events=POLLIN}, {fd=0, events=POLLIN}], 2, -1) = 1 ([{fd=4, revents=POLLHUP}])
poll([{fd=4, events=POLLIN}, {fd=0, events=POLLIN}], 2, -1) = 1 ([{fd=4, revents=POLLHUP}])
poll([{fd=4, events=POLLIN}, {fd=0, events=POLLIN}], 2, -1) = 1 ([{fd=4, revents=POLLHUP}])
... infinite

[benhillis]

@aont - I cannot reproduce this on 19013.

[aont]

@benhillis - I see. Since I don't use preview release, I cannot confirm. But somehow this is fixed on the next release. Thank you!