Re: Odd build breakage in 4.9-rc7

From: Jarod Wilson
Date: Wed Nov 30 2016 - 16:35:41 EST


On 2016-11-30 4:07 PM, Jarod Wilson wrote:
On 2016-11-30 3:52 PM, Paul Bolle wrote:
On Wed, 2016-11-30 at 12:24 -0500, Jarod Wilson wrote:
Up second, once we're past the above, building modules goes splat:

----8<----
$ make -s ARCH=x86_64 V=1 -j8 modules
...
ERROR: "module_put" [virt/lib/irqbypass.ko] undefined!
ERROR: "mutex_unlock" [virt/lib/irqbypass.ko] undefined!
ERROR: "mutex_lock" [virt/lib/irqbypass.ko] undefined!
...
----8<----

There are similar ERROR lines to the tune of 145k lines of output,
basically for every single module and symbol in the build. This breakage
was bisected to commit cd3caefb4663e3811d37cc2afad3cce642d60061, which
looks fairly innocuous, but when reverted, builds work fine again.

I ran into a modules build printing over 100K ERROR lines a month ago:

https://lkml.kernel.org/r/<1478165881-9263-1-git-send-email-pebolle@xxxxxxxxxx>


That had to do with setting TRIM_UNUSED_KSYMS and so unsetting
UNUSED_SYMBOLS,
as far as I could tell. Did you perhaps also have UNUSED_SYMBOLS unset
when
your modules build when splat?

I did indeed have CONFIG_TRIM_UNUSED_KSYMS=y and CONFIG_UNUSED_SYMBOLS
unset.

Just to confirm, with CONFIG_TRIM_UNUSED_KSYMS unset, the build behaves normally, no ERROR spew.

--
Jarod Wilson
jarod@xxxxxxxxxx