Documentation/core-api/kobject.rst states: "One important point cannot be overstated: every kobject must have a release() method, and the kobject must persist (in a consistent state) until that method is called. If these constraints are not met, the code is flawed. Note that the kernel will warn you if you forget to provide a release() method. Do not try to get rid of this warning by providing an "empty" release function."
Annotate struct kobj_type::release with __require_explicit_initialization so the compiler diagnoses any struct kobj_type initializer that omits .release. For the remaining legacy struct kobj_type definitions where the kobject is static, per-CPU, or embedded inside a devm- or parent-managed structure rather than freed by kobject_put(), explicitly initialize .release = NULL with a comment documenting why no release callback is provided. Link: https://lpc.events/event/20/contributions/2392/ Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers <[email protected]> --- arch/arm64/kernel/cpuinfo.c | 2 ++ drivers/acpi/sysfs.c | 2 ++ drivers/dma/ioat/sysfs.c | 2 ++ drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c | 4 ++++ drivers/infiniband/hw/hfi1/sysfs.c | 2 ++ drivers/infiniband/hw/usnic/usnic_ib_sysfs.c | 2 ++ drivers/parisc/pdc_stable.c | 2 ++ drivers/power/supply/ab8500_fg.c | 2 ++ drivers/soc/hisilicon/kunpeng_hccs.c | 6 ++++++ drivers/video/fbdev/omap2/omapfb/dss/display-sysfs.c | 2 ++ drivers/video/fbdev/omap2/omapfb/dss/manager-sysfs.c | 2 ++ drivers/video/fbdev/omap2/omapfb/dss/overlay-sysfs.c | 2 ++ fs/erofs/sysfs.c | 4 ++++ fs/f2fs/sysfs.c | 6 ++++++ fs/ocfs2/cluster/masklog.c | 2 ++ include/linux/kobject.h | 2 +- 16 files changed, 43 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 45c63f3d75c5..ab78efdb13f5 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -309,6 +309,8 @@ const struct seq_operations cpuinfo_op = { static const struct kobj_type cpuregs_kobj_type = { + /* info->kobj is embedded in per-CPU cpu_data; cpuid_cpu_offline() only calls kobject_del(). */ + .release = NULL, .sysfs_ops = &kobj_sysfs_ops, }; diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index dd4a99f09efe..7534d3f305ba 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -972,6 +972,8 @@ static struct attribute *hotplug_profile_attrs[] = { ATTRIBUTE_GROUPS(hotplug_profile); static const struct kobj_type acpi_hotplug_profile_ktype = { + /* hotplug->kobj is embedded in static struct acpi_scan_hotplug objects. */ + .release = NULL, .sysfs_ops = &kobj_sysfs_ops, .default_groups = hotplug_profile_groups, }; diff --git a/drivers/dma/ioat/sysfs.c b/drivers/dma/ioat/sysfs.c index e796ddb5383f..7fdd0ca36b98 100644 --- a/drivers/dma/ioat/sysfs.c +++ b/drivers/dma/ioat/sysfs.c @@ -167,6 +167,8 @@ static const struct attribute *const ioat_attrs[] = { ATTRIBUTE_GROUPS(ioat); const struct kobj_type ioat_ktype = { + /* ioatdma_chan is allocated via devm_kzalloc() rather than freed by kobject_put(). */ + .release = NULL, .sysfs_ops = &ioat_sysfs_ops, .default_groups = ioat_groups, }; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c index b15af318784b..0477468f12ae 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c @@ -789,6 +789,8 @@ static const struct sysfs_ops xcp_cfg_res_sysfs_ops = { }; static const struct kobj_type xcp_cfg_res_sysfs_ktype = { + /* xcp_res is embedded in struct amdgpu_xcp_cfg rather than freed individually by kobject_put(). */ + .release = NULL, .sysfs_ops = &xcp_cfg_res_sysfs_ops, .default_groups = xcp_cfg_res_sysfs_groups, }; @@ -1053,6 +1055,8 @@ static const struct attribute_group amdgpu_xcp_attrs_group = { }; static const struct kobj_type xcp_sysfs_ktype = { + /* xcp is embedded in struct amdgpu_xcp_mgr rather than freed individually by kobject_put(). */ + .release = NULL, .sysfs_ops = &kobj_sysfs_ops, }; diff --git a/drivers/infiniband/hw/hfi1/sysfs.c b/drivers/infiniband/hw/hfi1/sysfs.c index 372cfd13dc61..33b26650069d 100644 --- a/drivers/infiniband/hw/hfi1/sysfs.c +++ b/drivers/infiniband/hw/hfi1/sysfs.c @@ -608,6 +608,8 @@ static const struct sysfs_ops sde_sysfs_ops = { }; static struct kobj_type sde_ktype = { + /* sdma_engine is embedded in the dd->per_sdma array rather than freed by kobject_put(). */ + .release = NULL, .sysfs_ops = &sde_sysfs_ops, }; diff --git a/drivers/infiniband/hw/usnic/usnic_ib_sysfs.c b/drivers/infiniband/hw/usnic/usnic_ib_sysfs.c index fdb63a8fb997..234d8d9532aa 100644 --- a/drivers/infiniband/hw/usnic/usnic_ib_sysfs.c +++ b/drivers/infiniband/hw/usnic/usnic_ib_sysfs.c @@ -245,6 +245,8 @@ static struct attribute *usnic_ib_qpn_default_attrs[] = { ATTRIBUTE_GROUPS(usnic_ib_qpn_default); static struct kobj_type usnic_ib_qpn_type = { + /* usnic_ib_qp_grp is embedded in RDMA core-managed struct usnic_ib_qp_grp. */ + .release = NULL, .sysfs_ops = &usnic_ib_qpn_sysfs_ops, .default_groups = usnic_ib_qpn_default_groups, }; diff --git a/drivers/parisc/pdc_stable.c b/drivers/parisc/pdc_stable.c index 16f4496bca95..6d972c965c1e 100644 --- a/drivers/parisc/pdc_stable.c +++ b/drivers/parisc/pdc_stable.c @@ -484,6 +484,8 @@ ATTRIBUTE_GROUPS(paths_subsys); /* Specific kobject type for our PDC paths */ static const struct kobj_type ktype_pdcspath = { + /* pdcspath_entry instances are static; lifetime is not controlled by kobject_put(). */ + .release = NULL, .sysfs_ops = &pdcspath_attr_ops, .default_groups = paths_subsys_groups, }; diff --git a/drivers/power/supply/ab8500_fg.c b/drivers/power/supply/ab8500_fg.c index e6b5efdf5dc9..206ee2e392fb 100644 --- a/drivers/power/supply/ab8500_fg.c +++ b/drivers/power/supply/ab8500_fg.c @@ -2531,6 +2531,8 @@ static struct attribute *ab8500_fg_attrs[] = { ATTRIBUTE_GROUPS(ab8500_fg); static const struct kobj_type ab8500_fg_ktype = { + /* fg_kobject is embedded in devm-allocated struct ab8500_fg; ab8500_fg_sysfs_exit() only calls kobject_del(). */ + .release = NULL, .sysfs_ops = &ab8500_fg_sysfs_ops, .default_groups = ab8500_fg_groups, }; diff --git a/drivers/soc/hisilicon/kunpeng_hccs.c b/drivers/soc/hisilicon/kunpeng_hccs.c index 0cc2953d59a5..5d083d2b72ca 100644 --- a/drivers/soc/hisilicon/kunpeng_hccs.c +++ b/drivers/soc/hisilicon/kunpeng_hccs.c @@ -1038,6 +1038,8 @@ static struct attribute *hccs_port_default_attrs[] = { ATTRIBUTE_GROUPS(hccs_port_default); static const struct kobj_type hccs_port_type = { + /* hccs_port_info is allocated via devm_kcalloc() rather than freed by kobject_put(). */ + .release = NULL, .sysfs_ops = &hccs_comm_ops, .default_groups = hccs_port_default_groups, }; @@ -1110,6 +1112,8 @@ static struct attribute *hccs_die_default_attrs[] = { ATTRIBUTE_GROUPS(hccs_die_default); static const struct kobj_type hccs_die_type = { + /* hccs_die_info is allocated via devm_kcalloc() rather than freed by kobject_put(). */ + .release = NULL, .sysfs_ops = &hccs_comm_ops, .default_groups = hccs_die_default_groups, }; @@ -1213,6 +1217,8 @@ static struct attribute *hccs_chip_default_attrs[] = { ATTRIBUTE_GROUPS(hccs_chip_default); static const struct kobj_type hccs_chip_type = { + /* hccs_chip_info is allocated via devm_kcalloc() rather than freed by kobject_put(). */ + .release = NULL, .sysfs_ops = &hccs_comm_ops, .default_groups = hccs_chip_default_groups, }; diff --git a/drivers/video/fbdev/omap2/omapfb/dss/display-sysfs.c b/drivers/video/fbdev/omap2/omapfb/dss/display-sysfs.c index ae937854403b..3d787245f5b5 100644 --- a/drivers/video/fbdev/omap2/omapfb/dss/display-sysfs.c +++ b/drivers/video/fbdev/omap2/omapfb/dss/display-sysfs.c @@ -304,6 +304,8 @@ static const struct sysfs_ops display_sysfs_ops = { }; static struct kobj_type display_ktype = { + /* dssdev->kobj is embedded in struct omap_dss_device and zeroed in display_uninit_sysfs(). */ + .release = NULL, .sysfs_ops = &display_sysfs_ops, .default_groups = display_sysfs_groups, }; diff --git a/drivers/video/fbdev/omap2/omapfb/dss/manager-sysfs.c b/drivers/video/fbdev/omap2/omapfb/dss/manager-sysfs.c index 1b644be5fe2e..cf816e83e903 100644 --- a/drivers/video/fbdev/omap2/omapfb/dss/manager-sysfs.c +++ b/drivers/video/fbdev/omap2/omapfb/dss/manager-sysfs.c @@ -496,6 +496,8 @@ static const struct sysfs_ops manager_sysfs_ops = { }; static struct kobj_type manager_ktype = { + /* mgr->kobj is embedded in static managers[] and zeroed in dss_manager_kobj_uninit(). */ + .release = NULL, .sysfs_ops = &manager_sysfs_ops, .default_groups = manager_sysfs_groups, }; diff --git a/drivers/video/fbdev/omap2/omapfb/dss/overlay-sysfs.c b/drivers/video/fbdev/omap2/omapfb/dss/overlay-sysfs.c index 1da4fb1c77b4..9aa16b3dee5e 100644 --- a/drivers/video/fbdev/omap2/omapfb/dss/overlay-sysfs.c +++ b/drivers/video/fbdev/omap2/omapfb/dss/overlay-sysfs.c @@ -429,6 +429,8 @@ static const struct sysfs_ops overlay_sysfs_ops = { }; static struct kobj_type overlay_ktype = { + /* ovl->kobj is embedded in static overlays[]; dss_overlay_kobj_uninit() only calls kobject_del(). */ + .release = NULL, .sysfs_ops = &overlay_sysfs_ops, .default_groups = overlay_sysfs_groups, }; diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c index dfcec9376cd5..588d541e1713 100644 --- a/fs/erofs/sysfs.c +++ b/fs/erofs/sysfs.c @@ -238,6 +238,8 @@ static const struct kobj_type erofs_sb_ktype = { static const struct kobj_type erofs_ktype = { .default_groups = erofs_groups, .sysfs_ops = &erofs_attr_ops, + /* erofs_root is a static struct kset; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kset erofs_root = { @@ -247,6 +249,8 @@ static struct kset erofs_root = { static const struct kobj_type erofs_feat_ktype = { .default_groups = erofs_feat_groups, .sysfs_ops = &erofs_attr_ops, + /* erofs_feat is a static struct kobject; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kobject erofs_feat = { diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c index 811e350a1430..a66cef927c62 100644 --- a/fs/f2fs/sysfs.c +++ b/fs/f2fs/sysfs.c @@ -1653,6 +1653,8 @@ static const struct kobj_type f2fs_sb_ktype = { static const struct kobj_type f2fs_ktype = { .sysfs_ops = &f2fs_attr_ops, + /* f2fs_kset is a static struct kset; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kset f2fs_kset = { @@ -1667,6 +1669,8 @@ static const struct sysfs_ops f2fs_feat_attr_ops = { static const struct kobj_type f2fs_feat_ktype = { .default_groups = f2fs_feat_groups, .sysfs_ops = &f2fs_feat_attr_ops, + /* f2fs_feat is a static struct kobject; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kobject f2fs_feat = { @@ -1681,6 +1685,8 @@ static const struct sysfs_ops f2fs_tune_attr_ops = { static const struct kobj_type f2fs_tune_ktype = { .default_groups = f2fs_tune_groups, .sysfs_ops = &f2fs_tune_attr_ops, + /* f2fs_tune is a static struct kobject; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kobject f2fs_tune = { diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c index 563881ddbf00..e476fa7ffea6 100644 --- a/fs/ocfs2/cluster/masklog.c +++ b/fs/ocfs2/cluster/masklog.c @@ -147,6 +147,8 @@ static const struct sysfs_ops mlog_attr_ops = { static struct kobj_type mlog_ktype = { .default_groups = mlog_default_groups, .sysfs_ops = &mlog_attr_ops, + /* mlog_kset is a static struct kset; lifetime is not controlled by kobject_put(). */ + .release = NULL, }; static struct kset mlog_kset = { diff --git a/include/linux/kobject.h b/include/linux/kobject.h index 55e37a5d405e..e65331717e03 100644 --- a/include/linux/kobject.h +++ b/include/linux/kobject.h @@ -114,7 +114,7 @@ void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid) char *kobject_get_path(const struct kobject *kobj, gfp_t flag); struct kobj_type { - void (*release)(struct kobject *kobj); + void (*release)(struct kobject *kobj) __require_explicit_initialization; const struct sysfs_ops *sysfs_ops; const struct attribute_group **default_groups; const struct kobj_ns_type_operations *(*child_ns_type)(const struct kobject *kobj); -- 2.56.0.385.gd3acb90ef8-goog
