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

goroutine 84443 [running]:
panic({0x10ec220, 0x1e67c20})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0031a6ff0 sp=0xc0031a6f30 pc=0x436c1b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0031a7050 sp=0xc0031a6ff0 pc=0x44e23d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0x1ec6308?, 0xc0047fe780?)
	pkg/sentry/kernel/tty.go:54 +0x9d fp=0xc0031a70e0 sp=0xc0031a7050 pc=0x94b45d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0xff2e, 0xc0003be180, 0xc0003be190, {0xc0047fe000?, 0xc006b3ec10?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:411 +0x285 fp=0xc0031a7308 sp=0xc0031a70e0 pc=0xc895e5
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0003be190, 0xc002ee8000?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0x99 fp=0xc0031a7370 sp=0xc0031a7308 pc=0xc8bf99
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0003be190, {0x14c8e18, 0xc006f46a80}, {{0x14c30d0, 0xc002ee8000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x214 fp=0xc0031a7450 sp=0xc0031a7370 pc=0xc8b954
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0003be180, {0x14c8e18?, 0xc006f46a80?}, {{0x14c30d0, 0xc002ee8000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xbf fp=0xc0031a74d8 sp=0xc0031a7450 pc=0xc8881f
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0xc006c73520?, {0x14c8e18?, 0xc006f46a80?}, {{0x14c30d0, 0xc002ee8000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x5b fp=0xc0031a7538 sp=0xc0031a74d8 pc=0xc8a2db
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc00354de80, {0x14c8e18, 0xc006f46a80}, {{0x14c30d0, 0xc002ee8000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0x91 fp=0xc0031a75b8 sp=0xc0031a7538 pc=0x73fa31
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xffffffff?, 0xc00354de80, {{0x14c30d0, 0xc002ee8000}, {0x0, 0x1, 0x20000280, 0xff2e}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x85 fp=0xc0031a7778 sp=0xc0031a75b8 pc=0xa85ee5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc006f46a80, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x1c5 fp=0xc0031a7880 sp=0xc0031a7778 pc=0xa857c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc006f46a80, 0x1, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x755 fp=0xc0031a7c70 sp=0xc0031a7880 pc=0x942635
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc006f46a80, 0x85?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4a fp=0xc0031a7cd0 sp=0xc0031a7c70 pc=0x94386a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc003a22600?, 0x0?, {{0x3}, {0x20000280}, {0xff2e}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc0031a7d30 sp=0xc0031a7cd0 pc=0x943545
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00252d6c0?)
	pkg/sentry/kernel/task_syscall.go:257 +0x2f0 fp=0xc0031a7e28 sp=0xc0031a7d30 pc=0x9432b0
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc003d05a00?, 0xc006f46a80)
	pkg/sentry/kernel/task_run.go:265 +0x103e fp=0xc0031a7f60 sp=0xc0031a7e28 pc=0x9374de
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc006f46a80, 0x11b4)
	pkg/sentry/kernel/task_run.go:94 +0x1b8 fp=0xc0031a7fc0 sp=0xc0031a7f60 pc=0x935e78
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc0031a7fe0 sp=0xc0031a7fc0 pc=0x940e2a
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0031a7fe8 sp=0xc0031a7fe0 pc=0x46d5e1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0xef