On Wed, 27 Apr 2016, Stephen Rothwell wrote: > Hi Nicolas, > > On Tue, 26 Apr 2016 10:40:57 -0400 (EDT) Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote: > > > > If you can reproduce this build failure, could you try a make mrproper > > and attempt it again? I, too, would like to find an explanation and a > > way to reproduce. > > I reset my build tree to commit 9d67df654092 ("Merge remote-tracking > branch 'block/for-next'") and the build failed with: > > ERROR: ".local_clock" [drivers/vhost/vhost_net.ko] undefined! > ERROR: ".local_clock" [drivers/misc/cxl/cxl.ko] undefined! > > :-( > > So I did a "make mrproper" and did the build again. > > That built correctly. > [...] OK! After digging and diffing through 750 megabytes of make debug logs I finally found the explanation. The if_changed directive is useless against phony targets. @Stephen: could you replace the revert with the patch below in your tree? @Michal: could you fold the patch below into commit 2441e78b19 in your tree? diff --git a/Makefile b/Makefile index ca46af5cc0..3a7b9a93b2 100644 --- a/Makefile +++ b/Makefile @@ -953,7 +953,7 @@ include/generated/autoksyms.h: FORCE cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) quiet_cmd_link-vmlinux = LINK $@ -vmlinux: scripts/link-vmlinux.sh vmlinux_prereq FORCE +vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE +$(call if_changed,link-vmlinux) # Build samples along the rest of the kernel -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html