Re: Build failures with gcc 4.5 and older

From: Guenter Roeck
Date: Tue Aug 14 2018 - 21:02:45 EST

On 08/14/2018 04:20 PM, Linus Torvalds wrote:
On Tue, Aug 14, 2018 at 4:02 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

The m68k build still fails because 0cc3cd21657 ("cpu/hotplug: Boot HT
siblings at least once") was evidently never tested on CONFIG_SMP=n.
How could that come about - the patch is six weeks old??

Ehh, meet the joys of embargoes.

The code was tested (and people even found subtle arm64 problems due
to that testing), but because it couldn't be made public until today,
it didn't go through all the usual infrastructure we depend on.


kernel/cpu.c: In function 'boot_cpu_hotplug_init':
kernel/cpu.c:2275:2: error: 'struct cpuhp_cpu_state' has no member named 'booted_once'

it should be fixed now in -git.

@@ -490,6 +490,8 @@ struct mm_struct {
} __randomize_layout;

+ int wibble;

Can we call this something informative? Like

int __gcc_4_4_is_garbage_that_shouldnt_be_used;

or something?

That is, if we actually want to really drag out this whole pointless
pain of allowing ancient compilers?

Guys, at some point we need to switch to 4.6. The people who feel the
pain today *will* feel the pain at some point. Just get it over with

For my part I am all for making gcc 4.6 mandatory.