Hello, I have tried another small script out for the semantic patch language. This source code analysis approach points out that the function “gmap_find_shadow” is called two times by the function “gmap_shadow”. https://elixir.bootlin.com/linux/v5.7-rc3/source/arch/s390/mm/gmap.c#L1628 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/arch/s390/mm/gmap.c Null pointer checks are performed at these places. The function “gmap_find_shadow” is documented in the same source file that the pointer “ERR_PTR(-EAGAIN)” can eventually be returned. Are the referenced gmap data structures always initialised here? Regards, Markus
