sparse is throwing a very strange set of warnings like this on Linux kernel builds: include/linux/err.h:35:16: warning: dereference of noderef expression include/linux/err.h:30:23: warning: dereference of noderef expression ...with some experimentation, it seems that the issue is that sparse is built with CFLAGS that include -O2 and -fpic. With that combo, the modifiers field for the ctype generated in the IS_ERR and PTR_ERR expressions ends up corrupt (maybe uninitialized?) I suspect that this is sparse relying on some undefined behavior somewhere, but the code is convoluted and I haven't been able to pin down where the difference comes in. For now, I'm going to remove the -fpic flag, but longer term it would be good to understand what's going wrong here.
This bug appears to have been reported against 'rawhide' during the Fedora 22 development cycle. Changing version to '22'. More information and reason for this action is here: https://fedoraproject.org/wiki/Fedora_Program_Management/HouseKeeping/Fedora22
Fedora 22 changed to end-of-life (EOL) status on 2016-07-19. Fedora 22 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.
Reopening this bug. I think I might have found the problem (finally).
sparse-0.5.0-8.fc25 has been submitted as an update to Fedora 25. https://bodhi.fedoraproject.org/updates/FEDORA-2016-905f2517fe
sparse-0.5.0-8.fc24 has been submitted as an update to Fedora 24. https://bodhi.fedoraproject.org/updates/FEDORA-2016-234b480967
sparse-0.5.0-8.fc25 has been pushed to the Fedora 25 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-905f2517fe
sparse-0.5.0-8.fc24 has been pushed to the Fedora 24 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-234b480967
Fixed. The issue was an array in the code that was missing an element. When built with those options, the area beyond the array was no longer zeroed out. so we ended up getting back a nonsensical flags value.