When doing PT_SETREGS, we want to verify that the debugged thread is executing in usermode. b2f7ccf refactored things and flipped the relevant check around, which broke things that use PT_SETREGS (for example, stepping over breakpoints with sdb).
faccessat(2)
SIGCONT
symlinkat(2)
mkdirat(2)
readlinkat(2)
renameat(2)
sid
pgid
Credentials
pwritev(2)