panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x94b45d]

goroutine 486118 [running]:
panic({0x10ec220, 0x1e67c20})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0017ccff0 sp=0xc0017ccf30 pc=0x436c1b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0017cd050 sp=0xc0017ccff0 pc=0x44e23d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x1ec6308?, 0xc004502010?)
	pkg/sentry/kernel/tty.go:54 +0x9d fp=0xc0017cd0e0 sp=0xc0017cd050 pc=0x94b45d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x4b0, 0xc00432c000, 0xc00432c010, {0xc004502000?, 0xc000e85710?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x34e fp=0xc0017cd308 sp=0xc0017cd0e0 pc=0xc896ae
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc00432c010, 0xc004428000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x99 fp=0xc0017cd370 sp=0xc0017cd308 pc=0xc8bf99
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc00432c010, {0x14c8e18, 0xc003a63500}, {{0x14c30d0, 0xc004428000}, {0x0, 0x1, 0x20001ec0, 0x4b0}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x214 fp=0xc0017cd450 sp=0xc0017cd370 pc=0xc8b954
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc00432c000, {0x14c8e18?, 0xc003a63500?}, {{0x14c30d0, 0xc004428000}, {0x0, 0x1, 0x20001ec0, 0x4b0}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xbf fp=0xc0017cd4d8 sp=0xc0017cd450 pc=0xc8881f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x0?, {0x14c8e18?, 0xc003a63500?}, {{0x14c30d0, 0xc004428000}, {0x0, 0x1, 0x20001ec0, 0x4b0}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x5b fp=0xc0017cd538 sp=0xc0017cd4d8 pc=0xc8a2db
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc00460b080, {0x14c8e18, 0xc003a63500}, {{0x14c30d0, 0xc004428000}, {0x0, 0x1, 0x20001ec0, 0x4b0}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x91 fp=0xc0017cd5b8 sp=0xc0017cd538 pc=0x73fa31
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc00460b080, {{0x14c30d0, 0xc004428000}, {0x0, 0x1, 0x20001ec0, 0x4b0}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x85 fp=0xc0017cd778 sp=0xc0017cd5b8 pc=0xa85ee5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc003a63500, {{0x4}, {0x20001ec0}, {0x4b0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x1c5 fp=0xc0017cd880 sp=0xc0017cd778 pc=0xa857c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc003a63500, 0x1, {{0x4}, {0x20001ec0}, {0x4b0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x755 fp=0xc0017cdc70 sp=0xc0017cd880 pc=0x942635
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc003a63500, 0x85?, {{0x4}, {0x20001ec0}, {0x4b0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4a fp=0xc0017cdcd0 sp=0xc0017cdc70 pc=0x94386a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0x8fa11a?, 0xc007094620?, {{0x4}, {0x20001ec0}, {0x4b0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc0017cdd30 sp=0xc0017cdcd0 pc=0x943545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc0031ec340?)
	pkg/sentry/kernel/task_syscall.go:257 +0x2f0 fp=0xc0017cde28 sp=0xc0017cdd30 pc=0x9432b0
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc004458600?, 0xc003a63500)
	pkg/sentry/kernel/task_run.go:265 +0x103e fp=0xc0017cdf60 sp=0xc0017cde28 pc=0x9374de
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc003a63500, 0x42ed)
	pkg/sentry/kernel/task_run.go:94 +0x1b8 fp=0xc0017cdfc0 sp=0xc0017cdf60 pc=0x935e78
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc0017cdfe0 sp=0xc0017cdfc0 pc=0x940e2a
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0017cdfe8 sp=0xc0017cdfe0 pc=0x46d5e1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xef