panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x9d6041]

goroutine 46628 [running]:
panic({0x11ee280, 0x210cda0})
	GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc0021cd078 sp=0xc0021ccfb8 pc=0x436a3b
runtime.panicmem(...)
	GOROOT/src/runtime/panic.go:260
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0021cd0d8 sp=0xc0021cd078 pc=0x44e05d
gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0xc00152a288, 0xc001baa819?)
	pkg/sentry/kernel/tty.go:54 +0xa1 fp=0xc0021cd168 sp=0xc0021cd0d8 pc=0x9d6041
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6bdc5a, 0xc0002d0480, 0xc0002d0490, {0xc001baa7e0?, 0xc00384ca80?, 0x0?})
	pkg/sentry/fsimpl/devpts/line_discipline.go:409 +0x3c6 fp=0xc0021cd398 sp=0xc0021cd168 pc=0xd6e366
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0002d0490, 0xc00384ca80?)
	pkg/sentry/fsimpl/devpts/queue.go:219 +0xce fp=0xc0021cd400 sp=0xc0021cd398 pc=0xd7130e
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0002d0490, {0x15f5f58, 0xc00384ca80}, {{0x15f0490, 0xc003db6000}, {0x0, 0x1, 0x20000300, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/queue.go:183 +0x1f9 fp=0xc0021cd4b0 sp=0xc0021cd400 pc=0xd70bd9
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0002d0480, {0x15f5f58, 0xc00384ca80}, {{0x15f0490, 0xc003db6000}, {0x0, 0x1, 0x20000300, 0x58}, {0x0, ...}})
	pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xcd fp=0xc0021cd540 sp=0xc0021cd4b0 pc=0xd6d22d
gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x3?, {0x15f5f58?, 0xc00384ca80?}, {{0x15f0490, 0xc003db6000}, {0x0, 0x1, 0x20000300, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/fsimpl/devpts/master.go:134 +0x65 fp=0xc0021cd5a0 sp=0xc0021cd540 pc=0xd6f265
gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc002668b80, {0x15f5f58, 0xc00384ca80}, {{0x15f0490, 0xc003db6000}, {0x0, 0x1, 0x20000300, 0x58}, {0x0, ...}}, ...)
	pkg/sentry/vfs/file_description.go:674 +0xa5 fp=0xc0021cd620 sp=0xc0021cd5a0 pc=0x7738a5
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xb2e78f?, 0xc002668b80, {{0x15f0490, 0xc003db6000}, {0x0, 0x1, 0x20000300, 0x58}, {0x0, 0x1}}, ...)
	pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x8e fp=0xc0021cd7f0 sp=0xc0021cd620 pc=0xb4196e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc00384ca80, {{0x4}, {0x20000300}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x25a fp=0xc0021cd930 sp=0xc0021cd7f0 pc=0xb4111a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc00384ca80, 0x1, {{0x4}, {0x20000300}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc0021cdc70 sp=0xc0021cd930 pc=0x9cb66b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc00384ca80, 0x85?, {{0x4}, {0x20000300}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc0021cdcd0 sp=0xc0021cdc70 pc=0x9ccc54
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0021cdd78?, 0x9829e6?, {{0x4}, {0x20000300}, {0x58}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc0021cdd30 sp=0xc0021cdcd0 pc=0x9cc845
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000b73a00?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc0021cde28 sp=0xc0021cdd30 pc=0x9cc50c
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc002668a00?, 0xc00384ca80)
	pkg/sentry/kernel/task_run.go:265 +0x144a fp=0xc0021cdf60 sp=0xc0021cde28 pc=0x9be14a
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc00384ca80, 0x628)
	pkg/sentry/kernel/task_run.go:94 +0x21c fp=0xc0021cdfc0 sp=0xc0021cdf60 pc=0x9bc65c
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc0021cdfe0 sp=0xc0021cdfc0 pc=0x9c9aea
runtime.goexit()
	src/runtime/asm_amd64.s:1598 +0x1 fp=0xc0021cdfe8 sp=0xc0021cdfe0 pc=0x46d401
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:377 +0x105