asmlinkage_protect sys_io_getevents

Use asmlinkage_protect in sys_io_getevents, because GCC for i386 with
CONFIG_FRAME_POINTER=n can decide to clobber an argument word on the
stack, i.e. the user struct pt_regs. Here the problem is not a tail
call, but just the compiler's use of the stack when it inlines and
optimizes the body of the called function. This seems to avoid it.

Signed-off-by: Roland McGrath <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/aio.c

···
 		put_ioctx(ioctx);
 	}
 
+	asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
 	return ret;
 }