panic: close of nil channel (2)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
gvisor	panic: close of nil channel	syz			6	1494d	1499d	0/26	fixed on 2020/04/24 19:17

panic: close of nil channel

goroutine 76689 [running]:
panic(0x10f65e0, 0x13cb7d0)
	GOROOT/src/runtime/panic.go:1064 +0x470 fp=0xc00319fda0 sp=0xc00319fce8 pc=0x437030
runtime.closechan(0x0)
	GOROOT/src/runtime/chan.go:354 +0x276 fp=0xc00319fde0 sp=0xc00319fda0 pc=0x406336
gvisor.dev/gvisor/pkg/sentry/mm.(*AIOContext).checkForDone(...)
	pkg/sentry/mm/aio_context.go:151
gvisor.dev/gvisor/pkg/sentry/mm.(*AIOContext).CancelPendingRequest(0xc000a517d0)
	pkg/sentry/mm/aio_context.go:245 +0xce fp=0xc00319fe20 sp=0xc00319fde0 pc=0x88b94e
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.getAIOCallback.func1(0x140eaa0, 0xc000989e80)
	pkg/sentry/syscalls/linux/vfs2/aio.go:208 +0x16c fp=0xc00319ffa0 sp=0xc00319fe20 pc=0xe8dfec
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).QueueAIO.func1(0xc00021c8c0, 0x140eaa0, 0xc000989e80, 0xc00025e28c)
	pkg/sentry/kernel/aio.go:33 +0x44 fp=0xc00319ffc0 sp=0xc00319ffa0 pc=0xa657c4
runtime.goexit()
	src/runtime/asm_amd64.s:1374 +0x1 fp=0xc00319ffc8 sp=0xc00319ffc0 pc=0x4705a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).QueueAIO
	pkg/sentry/kernel/aio.go:31 +0xf4