panic: Incrementing non-positive count ADDR on kernel.ProcessGroup (2)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
gvisor	panic: Incrementing non-positive count ADDR on kernel.ProcessGroup	C			12	1401d	1401d	14/26	fixed on 2021/02/10 20:40
panic: Incrementing non-positive count 0xc009bc4080 on kernel.ProcessGroup

goroutine 1257488 [running]:
panic(0x1044d80, 0xc08e4eef00)
	GOROOT/src/runtime/panic.go:1065 +0x565 fp=0xc007c81520 sp=0xc007c81458 pc=0x437c65
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroupRefs).IncRef(0xc009bc4080)
	bazel-out/k8-fastbuild-ST-4c64f0b3d5c7/bin/pkg/sentry/kernel/process_group_refs.go:80 +0x15f fp=0xc007c81598 sp=0xc007c81520 pc=0x9871bf
gvisor.dev/gvisor/pkg/sentry/kernel.(*ProcessGroup).incRefWithParent(...)
	pkg/sentry/kernel/sessions.go:143
gvisor.dev/gvisor/pkg/sentry/kernel.(*TaskSet).newTask(0xc0002feb40, 0xc007c81950, 0x0, 0x0, 0x0)
	pkg/sentry/kernel/task_start.go:203 +0x93a fp=0xc007c816b0 sp=0xc007c81598 pc=0x9b2a7a
gvisor.dev/gvisor/pkg/sentry/kernel.(*TaskSet).NewTask(0xc0002feb40, 0x13c9fa0, 0xc008e62000, 0xc007c81950, 0x11, 0xc08e4eeec0, 0xc00bbdf000)
	pkg/sentry/kernel/task_start.go:105 +0x39 fp=0xc007c81700 sp=0xc007c816b0 pc=0x9b1f79
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Clone(0xc008e62000, 0xc007c81a40, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/kernel/task_clone.go:312 +0x805 fp=0xc007c81a10 sp=0xc007c81700 pc=0x999e85
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.clone(0xc008e62000, 0x11, 0x0, 0x0, 0x0, 0x0, 0x44263c, 0xc0075de600, 0x300000002, 0xc0075de600)
	pkg/sentry/syscalls/linux/sys_thread.go:230 +0x158 fp=0xc007c81aa8 sp=0xc007c81a10 pc=0xa3eeb8
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Fork(0xc008e62000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3d, 0x9cbbf, 0xc007c81bf4, ...)
	pkg/sentry/syscalls/linux/sys_thread.go:238 +0x45 fp=0xc007c81b08 sp=0xc007c81aa8 pc=0xa3ef65
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc008e62000, 0x39, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x12342a0, ...)
	pkg/sentry/kernel/task_syscall.go:102 +0x13c fp=0xc007c81c68 sp=0xc007c81b08 pc=0x9b45dc
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc008e62000, 0x39, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/kernel/task_syscall.go:237 +0x66 fp=0xc007c81cf0 sp=0xc007c81c68 pc=0x9b57a6
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc008e62000, 0x39, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xe2c32e, 0xc0068177e0)
	pkg/sentry/kernel/task_syscall.go:197 +0x98 fp=0xc007c81d50 sp=0xc007c81cf0 pc=0x9b5358
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc008e62000, 0x2, 0xc008e62000)
	pkg/sentry/kernel/task_syscall.go:172 +0x15c fp=0xc007c81e20 sp=0xc007c81d50 pc=0x9b4cfc
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc008e62000, 0x139fd80, 0x0)
	pkg/sentry/kernel/task_run.go:282 +0xca5 fp=0xc007c81f60 sp=0xc007c81e20 pc=0x9a9505
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc008e62000, 0x624)
	pkg/sentry/kernel/task_run.go:97 +0x1af fp=0xc007c81fd0 sp=0xc007c81f60 pc=0x9a816f
runtime.goexit()
	src/runtime/asm_amd64.s:1371 +0x1 fp=0xc007c81fd8 sp=0xc007c81fd0 pc=0x472821
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:327 +0xfe