[OE-core] [RFC] Preventing race when compiling external kernel modules

[Richard Purdie]

On Fri, 2011-10-14 at 12:47 +0200, Anders Darander wrote:
> * Anders Darander <anders at chargestorm.se> [111014 09:55]:
> > In our local tree, I've circumvented this race by applying a patch like
> > [3]. (Well, we could likely have put the lock in do_make_scripts()
> > instead of module_do_compile(), as we have done currently). Obviously,
> > I'm not proposing to apply this patch, as it depends on lockfile from
> > the procmail-package (host-package).
> 
> Just to confirm, it seems (after a very few tests) that it indeed is
> enough to guard the do_make_scripts() with the lock.
> 
> However, the question on how to make the real solution remains...

I've not tested this but it might give you enough info to test
something:

(Basic idea is to promote that function to a task, then apply a lock to
it).

diff --git a/meta/classes/module.bbclass b/meta/classes/module.bbclass
index 572df0d..5602e74 100644
--- a/meta/classes/module.bbclass
+++ b/meta/classes/module.bbclass
@@ -14,8 +14,10 @@ do_make_scripts() {
                   -C ${STAGING_KERNEL_DIR} scripts
 }
 
+addtask make_scripts before compile
+do_make_scripts[lockfiles] = "${TMPDIR}/kernel-scripts.lock"
+
 module_do_compile() {
-       do_make_scripts
        unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
        oe_runmake KERNEL_PATH=${STAGING_KERNEL_DIR}   \
                   KERNEL_SRC=${STAGING_KERNEL_DIR}    \


Cheers,

Richard