syzbot

panic: invalid allocation length: 0x0

goroutine 227 [running]:
panic({0xfe7060, 0xc0005b6020})
	GOROOT/src/runtime/panic.go:1147 +0x3a8 fp=0xc000db5090 sp=0xc000db4fd0 pc=0x435148
gvisor.dev/gvisor/pkg/sentry/pgalloc.(*MemoryFile).Allocate(0xc000c4f878, 0xc0000e2280, {0x8d7a00, 0xc000776c50})
	pkg/sentry/pgalloc/pgalloc.go:417 +0x545 fp=0xc000db51a0 sp=0xc000db5090 pc=0x7d28e5
gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).getPMAsInternalLocked(0xc000c4f000, {0x1394d10, 0xc000c78000}, {0xc000c4f080, 0x8975a7}, {0x8d7527, 0xc00039a4e0}, {0x0, 0x1, 0x0})
	pkg/sentry/mm/pma.go:243 +0x1746 fp=0xc000db55c8 sp=0xc000db51a0 pc=0x880046
gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).getPMAsLocked(0xc000776000, {0x1394d10, 0xc000c78000}, {0xc000c4f080, 0xc000db56a0}, {0xcb3b8a, 0xc000db57b0}, {0x0, 0x1, 0x0})
	pkg/sentry/mm/pma.go:125 +0xbf fp=0xc000db5658 sp=0xc000db55c8 pc=0x87e31f
gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).withInternalMappings(0xc000c4f000, {0x1394d10, 0xc000c78000}, {0x0, 0x0}, {0x0, 0x46, 0xc1}, 0x0, 0x1214c68)
	pkg/sentry/mm/io.go:542 +0x2e5 fp=0xc000db5748 sp=0xc000db5658 pc=0x879505
gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).EnsurePMAsExist(0xcb3b00, {0x1394d10, 0xc000c78000}, 0xc0000e2280, 0xc00039a2a0, {0x0, 0x12})
	pkg/sentry/mm/io.go:322 +0x77 fp=0xc000db5790 sp=0xc000db5748 pc=0x878377
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.getdents(0xc000c78000, {{0x3}, {0x0}, {0x0}, {0x0}, {0x0}, {0x0}}, 0x0)
	pkg/sentry/syscalls/linux/vfs2/getdents.go:53 +0x131 fp=0xc000db5858 sp=0xc000db5790 pc=0xcb6a51
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Getdents(0xc000051800, {{0x3}, {0x0}, {0x0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/vfs2/getdents.go:31 +0x38 fp=0xc000db58a8 sp=0xc000db5858 pc=0xcb6898
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000c78000, 0x4e, {{0x3}, {0x0}, {0x0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x825 fp=0xc000db5cb0 sp=0xc000db58a8 pc=0x9ba365
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000c78000, 0x0, {{0x3}, {0x0}, {0x0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4d fp=0xc000db5d20 sp=0xc000db5cb0 pc=0x9bb68d
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc000c5e0b8, 0x1394d10, {{0x3}, {0x0}, {0x0}, {0x0}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc000db5d80 sp=0xc000db5d20 pc=0x9bb345
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000c78000)
	pkg/sentry/kernel/task_syscall.go:257 +0x31a fp=0xc000db5e48 sp=0xc000db5d80 pc=0x9bb07a
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000d9c080, 0xc000c78000)
	pkg/sentry/kernel/task_run.go:247 +0xe45 fp=0xc000db5f70 sp=0xc000db5e48 pc=0x9af145
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000c78000)
	pkg/sentry/kernel/task_run.go:90 +0x1a2 fp=0xc000db5fc8 sp=0xc000db5f70 pc=0x9adca2
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start·dwrap·239()
	pkg/sentry/kernel/task_start.go:364 +0x26 fp=0xc000db5fe0 sp=0xc000db5fc8 pc=0x9b8ac6
runtime.goexit()
	src/runtime/asm_amd64.s:1581 +0x1 fp=0xc000db5fe8 sp=0xc000db5fe0 pc=0x4692a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:364 +0xe7