panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1a92ed7]

goroutine 240 [running]:
panic({0x3192a0, 0x26473b0})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0009569a8 sp=0xc0009568e8 pc=0x125ecbb
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc000956a08 sp=0xc0009569a8 pc=0x1277b7d
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).SendSignal(0x0, 0xc000956c58)
	pkg/sentry/kernel/sessions.go:237 +0x57 fp=0xc000956b58 sp=0xc000956a08 pc=0x1a92ed7
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x123564a, 0xc000278000, 0xc000278010, {0xc00093a0c0, 0x58, 0x58})
	pkg/sentry/fsimpl/devpts/line_discipline.go:402 +0x4d6 fp=0xc000956db0 sp=0xc000956b58 pc=0x1ffcd76
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc000278010, 0xc000a2f000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x19f fp=0xc000956e60 sp=0xc000956db0 pc=0x2000ebf
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc000278010, {0x819e98, 0xc0002c0000}, {{0x814150, 0xc000a2f000}, {0x0, 0x1, 0x20000140, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x269 fp=0xc000956f98 sp=0xc000956e60 pc=0x2000469
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc000278000, {0x819e98, 0xc0002c0000}, {{0x814150, 0xc000a2f000}, {0x0, 0x1, 0x20000140, 0x58}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:217 +0xc6 fp=0xc000957030 sp=0xc000956f98 pc=0x1ffb8e6
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc000342a00, {0x819e98, 0xc0002c0000}, {{0x814150, 0xc000a2f000}, {0x0, 0x1, 0x20000140, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0xc5 fp=0xc0009570b0 sp=0xc000957030 pc=0x1ffe3c5
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc000342a00, {0x819e98, 0xc0002c0000}, {{0x814150, 0xc000a2f000}, {0x0, 0x1, 0x20000140, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x125 fp=0xc000957180 sp=0xc0009570b0 pc=0x178d805
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0x1cb67c0?, 0xc000342a00, {{0x814150, 0xc000a2f000}, {0x0, 0x1, 0x20000140, 0x58}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x9d fp=0xc000957370 sp=0xc000957180 pc=0x1cdc67d
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc0002c0000, {{0x3}, {0x20000140}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x275 fp=0xc0009574d8 sp=0xc000957370 pc=0x1cdbd35
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc0002c0000, 0x1, {{0x3}, {0x20000140}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x9b9 fp=0xc0009579b8 sp=0xc0009574d8 pc=0x1ad3f19
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc0002c0000, 0x0?, {{0x3}, {0x20000140}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x7d fp=0xc000957a50 sp=0xc0009579b8 pc=0x1ad5cfd
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0004601a0?, 0xc0002744b0?, {{0x3}, {0x20000140}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x8f fp=0xc000957ac8 sp=0xc000957a50 pc=0x1ad56af
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc0002c0000)
	pkg/sentry/kernel/task_syscall.go:257 +0x4c5 fp=0xc000957bf0 sp=0xc000957ac8 pc=0x1ad5245
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc0002c0000?, 0xc0002c0000)
	pkg/sentry/kernel/task_run.go:265 +0x1d4b fp=0xc000957ec8 sp=0xc000957bf0 pc=0x1abfc8b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc0002c0000, 0xe)
	pkg/sentry/kernel/task_run.go:94 +0x36b fp=0xc000957fb0 sp=0xc000957ec8 pc=0x1abd5ab
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x48 fp=0xc000957fe0 sp=0xc000957fb0 pc=0x1ad1a28
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc000957fe8 sp=0xc000957fe0 pc=0x1297b61
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x1ad