sparse multiple address spaces?

[Randy Dunlap <rdunlap@xxxxxxxxxxxxx>]

On Linux kernel tree v5.9-rc1, with sparse v0.6.2-180-g49f7e13a,
I see this sparse warning which I don't grok:

../include/uapi/asm-generic/signal-defs.h:19:29: CK: error: multiple address spaces given

for this source code:

typedef void __signalfn_t(int);
typedef __signalfn_t __user *__sighandler_t; <<<<< line 19

Are there multiple address spaces there?  What are they?



or: is the warning related to the other nearby warnings?  (e.g.:)

../kernel/signal.c:541:53: CK: warning: incorrect type in initializer (different address spaces)
../kernel/signal.c:541:53: CK:    expected struct k_sigaction *ka
../kernel/signal.c:541:53: CK:    got struct k_sigaction [noderef] __rcu *
../include/uapi/asm-generic/signal-defs.h:19:29: CK: error: multiple address spaces given
../kernel/signal.c:694:33: CK: warning: incorrect type in argument 1 (different address spaces)
../kernel/signal.c:694:33: CK:    expected struct spinlock [usertype] *lock
../kernel/signal.c:694:33: CK:    got struct spinlock [noderef] __rcu *


thanks.
-- 
~Randy