Recently two patches [1] [2] have hit a case of mistakenly picking an IOCTL number which was already in-use. This is hard to debug because the last definition wins and there is no indication that there is a conflict. Fix this by enabling -Werror=override-init for the IOCTL table. When there is a duplicate entry, the compiler now errors out: CC [M] drivers/gpu/drm/drm_ioctl.o drivers/gpu/drm/drm_ioctl.c:555:33: error: initialized field overwritten [-Werror=override-init] 555 | [DRM_IOCTL_NR(ioctl)] = { \ | ^ drivers/gpu/drm/drm_ioctl.c:708:9: note: in expansion of macro ‘DRM_IOCTL_DEF’ 708 | DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_EVENTFD, drm_syncobj_reset_ioctl, | ^~~~~~~~~~~~~ drivers/gpu/drm/drm_ioctl.c:555:33: note: (near initialization for ‘drm_ioctls[207]’) 555 | [DRM_IOCTL_NR(ioctl)] = { \ | ^ drivers/gpu/drm/drm_ioctl.c:708:9: note: in expansion of macro ‘DRM_IOCTL_DEF’ 708 | DRM_IOCTL_DEF(DRM_IOCTL_SYNCOBJ_EVENTFD, drm_syncobj_reset_ioctl, | ^~~~~~~~~~~~~ cc1: some warnings being treated as errors [1]: https://lore.kernel.org/dri-devel/20230714111257.11940-1-contact@xxxxxxxxxxx/ [2]: https://lore.kernel.org/dri-devel/vVFDBgHpdcB0vOwnl02QPOFmAZPEbIV56E_wQ8B012K2GZ-fAGyG0JMbSrMu3-IcKYVf0JpJyrf71e6KFHfeMoSPJlYRACxlxy91eW9c6Fc=@emersion.fr/ Signed-off-by: Simon Ser <contact@xxxxxxxxxxx> Cc: Erik Kurzinger <ekurzinger@xxxxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx> Cc: Christian König <christian.koenig@xxxxxxx> --- drivers/gpu/drm/drm_ioctl.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index f03ffbacfe9b..cd485eb54d2a 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -566,6 +566,8 @@ static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv) #endif /* Ioctl table */ +#pragma GCC diagnostic push +#pragma GCC diagnostic error "-Woverride-init" static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, DRM_RENDER_ALLOW), DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0), @@ -718,6 +720,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_MODE_GET_LEASE, drm_mode_get_lease_ioctl, DRM_MASTER), DRM_IOCTL_DEF(DRM_IOCTL_MODE_REVOKE_LEASE, drm_mode_revoke_lease_ioctl, DRM_MASTER), }; +#pragma GCC diagnostic pop #define DRM_CORE_IOCTL_COUNT ARRAY_SIZE(drm_ioctls) -- 2.41.0