panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x9d6041] goroutine 1386655 [running]: panic({0x11ee280, 0x210cda0}) GOROOT/src/runtime/panic.go:987 +0x3bb fp=0xc002129078 sp=0xc002128fb8 pc=0x436a3b runtime.panicmem(...) GOROOT/src/runtime/panic.go:260 runtime.sigpanic() GOROOT/src/runtime/signal_unix.go:837 +0x37d fp=0xc0021290d8 sp=0xc002129078 pc=0x44e05d gvisor.dev/gvisor/pkg/sentry/kernel.(*TTY).SignalForegroundProcessGroup(0xc0026914b8, 0xc005a1b4b4?) pkg/sentry/kernel/tty.go:54 +0xa1 fp=0xc002129168 sp=0xc0021290d8 pc=0x9d6041 gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*inputQueueTransformer).transform(0x6bdc5a, 0xc0003da180, 0xc0003da190, {0xc005a1b4a0?, 0xc0099c3500?, 0x0?}) pkg/sentry/fsimpl/devpts/line_discipline.go:407 +0x445 fp=0xc002129398 sp=0xc002129168 pc=0xd6e3e5 gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).pushWaitBufLocked(0xc0003da190, 0xc0099c3500?) pkg/sentry/fsimpl/devpts/queue.go:219 +0xce fp=0xc002129400 sp=0xc002129398 pc=0xd7130e gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*queue).write(0xc0003da190, {0x15f5f58, 0xc0099c3500}, {{0x15f0490, 0xc009ca3000}, {0x0, 0x1, 0x200001c0, 0x15c}, {0x0, ...}}, ...) pkg/sentry/fsimpl/devpts/queue.go:183 +0x1f9 fp=0xc0021294b0 sp=0xc002129400 pc=0xd70bd9 gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*lineDiscipline).inputQueueWrite(0xc0003da180, {0x15f5f58, 0xc0099c3500}, {{0x15f0490, 0xc009ca3000}, {0x0, 0x1, 0x200001c0, 0x15c}, {0x0, ...}}) pkg/sentry/fsimpl/devpts/line_discipline.go:220 +0xcd fp=0xc002129540 sp=0xc0021294b0 pc=0xd6d22d gvisor.dev/gvisor/pkg/sentry/fsimpl/devpts.(*masterFileDescription).Write(0x3?, {0x15f5f58?, 0xc0099c3500?}, {{0x15f0490, 0xc009ca3000}, {0x0, 0x1, 0x200001c0, 0x15c}, {0x0, ...}}, ...) pkg/sentry/fsimpl/devpts/master.go:134 +0x65 fp=0xc0021295a0 sp=0xc002129540 pc=0xd6f265 gvisor.dev/gvisor/pkg/sentry/vfs.(*FileDescription).Write(0xc005fbd280, {0x15f5f58, 0xc0099c3500}, {{0x15f0490, 0xc009ca3000}, {0x0, 0x1, 0x200001c0, 0x15c}, {0x0, ...}}, ...) pkg/sentry/vfs/file_description.go:674 +0xa5 fp=0xc002129620 sp=0xc0021295a0 pc=0x7738a5 gvisor.dev/gvisor/pkg/sentry/syscalls/linux.write(0xb2e78f?, 0xc005fbd280, {{0x15f0490, 0xc009ca3000}, {0x0, 0x1, 0x200001c0, 0x15c}, {0x0, 0x1}}, ...) pkg/sentry/syscalls/linux/sys_read_write.go:347 +0x8e fp=0xc0021297f0 sp=0xc002129620 pc=0xb4196e gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Write(0xc0099c3500, {{0x3}, {0x200001c0}, {0x15c}, {0x0}, {0x0}, {0x0}}) pkg/sentry/syscalls/linux/sys_read_write.go:316 +0x25a fp=0xc002129930 sp=0xc0021297f0 pc=0xb4111a gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc0099c3500, 0x1, {{0x3}, {0x200001c0}, {0x15c}, {0x0}, {0x0}, {0x0}}) pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc002129c70 sp=0xc002129930 pc=0x9cb66b gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc0099c3500, 0x85?, {{0x3}, {0x200001c0}, {0x15c}, {0x0}, {0x0}, {0x0}}) pkg/sentry/kernel/task_syscall.go:322 +0x54 fp=0xc002129cd0 sp=0xc002129c70 pc=0x9ccc54 gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc002129d78?, 0x9829e6?, {{0x3}, {0x200001c0}, {0x15c}, {0x0}, {0x0}, {0x0}}) pkg/sentry/kernel/task_syscall.go:282 +0x85 fp=0xc002129d30 sp=0xc002129cd0 pc=0x9cc845 gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc0014c3380?) pkg/sentry/kernel/task_syscall.go:257 +0x3ac fp=0xc002129e28 sp=0xc002129d30 pc=0x9cc50c gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc005fbd200?, 0xc0099c3500) pkg/sentry/kernel/task_run.go:265 +0x144a fp=0xc002129f60 sp=0xc002129e28 pc=0x9be14a gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc0099c3500, 0x702c) pkg/sentry/kernel/task_run.go:94 +0x21c fp=0xc002129fc0 sp=0xc002129f60 pc=0x9bc65c gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1() pkg/sentry/kernel/task_start.go:377 +0x2a fp=0xc002129fe0 sp=0xc002129fc0 pc=0x9c9aea runtime.goexit() src/runtime/asm_amd64.s:1598 +0x1 fp=0xc002129fe8 sp=0xc002129fe0 pc=0x46d401 created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start pkg/sentry/kernel/task_start.go:377 +0x105