panic: runtime error: index out of range

goroutine 319305 [running]:
unicode/utf8.EncodeRune(0xc000d4e1e0, 0x1, 0x8, 0xc0000000cf, 0x1)
DIAGNOSIS:
I0403 19:20:28.688023   31595 x:0] ***************************
I0403 19:20:28.688164   31595 x:0] Args: [/syzkaller/managers/ptrace-proxy-sandbox-race/current/image -root /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=ptrace -file-access=shared -network=sandbox debug -stacks ci-gvisor-ptrace-proxy-sandbox-race-2]
I0403 19:20:28.688224   31595 x:0] Version release-20190304.1-78-gc4caccd54042
I0403 19:20:28.688243   31595 x:0] PID: 31595
I0403 19:20:28.688260   31595 x:0] UID: 0, GID: 0
I0403 19:20:28.688275   31595 x:0] Configuration:
I0403 19:20:28.688287   31595 x:0] 		RootDir: /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root
I0403 19:20:28.688332   31595 x:0] 		Platform: ptrace
I0403 19:20:28.688370   31595 x:0] 		FileAccess: shared, overlay: false
I0403 19:20:28.688405   31595 x:0] 		Network: sandbox, logging: false
I0403 19:20:28.688442   31595 x:0] 		Strace: false, max size: 1024, syscalls: []
I0403 19:20:28.688465   31595 x:0] ***************************
D0403 19:20:28.688541   31595 x:0] Load container "/syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root" "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0403 19:20:28.694488   31595 x:0] Signal container "ci-gvisor-ptrace-proxy-sandbox-race-2": signal 0
D0403 19:20:28.694555   31595 x:0] Signal sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0403 19:20:28.694581   31595 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0403 19:20:28.695410   31595 x:0] urpc: successfully marshalled 117 bytes.
I0403 19:20:28.943094   31595 x:0] Found sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2", PID: 18149
I0403 19:20:28.943150   31595 x:0] Retrieving sandbox stacks
D0403 19:20:28.943189   31595 x:0] Stacks sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0403 19:20:28.943226   31595 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0403 19:20:28.943386   31595 x:0] urpc: successfully marshalled 36 bytes.
W0403 19:20:28.980928   31595 x:0] FATAL ERROR: retrieving stacks: getting sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2" stacks: urpc method "debug.Stacks" failed: connection reset by peer
retrieving stacks: getting sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2" stacks: urpc method "debug.Stacks" failed: connection reset by peer