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Wysocki" Cc: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Nayna Jain , Srish Srinivasan , Mimi Zohar , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Nathan Chancellor , Nick Desaulniers , Viresh Kumar , Zhongqiu Han , Alexander Aring , Felix Kuehling , "=?UTF-8?q?Christian=20K=C3=B6nig?=" , Zhihao Cheng , Sumanth Korikkar , Bill Wendling , Justin Stitt , driver-core@lists.linux.dev, llvm@lists.linux.dev, linux-hardening@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, linux-s390@vger.kernel.org, gfs2@lists.linux.dev, xen-devel@lists.xenproject.org, linux-mtd@lists.infradead.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Ian Rogers Content-Type: text/plain; charset="UTF-8" Clang supports the 'require_explicit_initialization' attribute on struct fields to enforce that the field is explicitly initialized when an aggregate object is constructed, emitting -Wuninitialized-explicit-init (enabled by default) if the field is omitted. Following discussion at the Linux Plumbers Conference [1], patch 1 adds the attribute to include/linux/compiler_attributes.h as __must_init. In v1 it was called __require_explicit_initialization. Kees picked up that patch with a first seq_file user [2], and in that thread Greg suggested the shorter __must_init spelling, which Kees and Miguel agreed to. As the attribute did not land in the v7.4 merge window, Kees asked that this series carry the renamed attribute. As Documentation/core-api/kobject.rst notes: "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." Annotating struct kobj_type::release caught struct kobj_type definitions across the tree that omitted .release: - Patches 2-8 fix struct kobj_type definitions where dynamically allocated kobjects, ksets, or enclosing structures were either leaked on kobject_put(), freed prematurely before kobject release, or missing proper static initializers. - Patch 9 annotates struct kobj_type::release with __must_init and explicitly sets .release = NULL (with explanatory comments prefixed with "Pre-existing:") on the remaining legacy struct kobj_type definitions whose kobjects are static, per-CPU, permanent firmware structures, or embedded in devm- or parent-managed allocations. Danilo Krummrich offered to route the series as a whole through the driver-core tree [3]. Subsystem maintainer Acked-by tags are still needed (and would be much appreciated!) for the following three patches: - Patch 2: powerpc/secvar: Add missing kobject release callback to secvar_ktype - Patch 3: sh: sq: Add missing kobject release callback to ktype_percpu_entry - Patch 6: xen/sys-hypervisor: Add release callback to hyp_sysfs_kobj_type Note on tool use: An LLM coding assistant was used to help audit the compiler diagnostics across the tree, draft the fixes and changelog descriptions, and verify builds and review feedback. Changes in v3: - Rebased on v7.4-rc1. - Note in cover letter that patches 2 (powerpc/secvar), 3 (sh: sq), and 6 (xen/sys-hypervisor) are still awaiting subsystem Acked-by tags for merging through the driver-core tree, and CC those maintainers on the cover letter. - Patch 1: Add Reviewed-by from Kees Cook; clarify that LLVM issue #232483 affects Clang versions prior to its upstream fix (pointed out by Nathan Chancellor). - Patch 4 (cpufreq): Drop obsolete reference to cpufreq_governor_dbs in the commit message per Zhongqiu Han; add Reviewed-by from Zhongqiu Han and Acked-by from Rafael J. Wysocki and Viresh Kumar. - Patch 5 (dlm): Add Acked-by from Alexander Aring. - Patch 8 (drm/amdkfd): Add Reviewed-by from Felix Kuehling. - Patch 9 (kobject): Fix omapfb manager-sysfs.c and overlay-sysfs.c comments to describe managers[] and overlays[] as dynamically allocated rather than static and note the CONFIG_DEBUG_KOBJECT_RELEASE hazard, fix a struct-vs-member wording nit in usnic_ib_sysfs.c, and generalize the commit message note on CONFIG_DEBUG_KOBJECT_RELEASE (reported by Sashiko). Changes in v2: - Rebased on v7.3-16928-g83f32c773255 (v7.4 merge window). - Patch 1: Rename __require_explicit_initialization to __must_init per Greg Kroah-Hartman; document the Clang >= 20 requirement per Miguel Ojeda; note the Clang gap for file-scope objects without an initializer reported by Kees Cook; add tags from v1 and from Kees's posting. - Move LLM assistance attribution from Assisted-by tags to this cover letter per commit 1e035297ffda ("docs: remove Assisted-by references"). - Patch 4 (cpufreq): Use "cpufreq: governor:" prefix, drop Fixes tag, fix typo, and remove the redundant runtime assignment in cpufreq_dbs_governor_init() per Zhongqiu Han. - Dropped v1 patch 5 (ACPI: CPPC), already fixed upstream by commit 27954e29d7de ("ACPI: CPPC: Release CPC descriptors through kobject"). - Patch 5 (dlm): Call kobject_del() before dlm_recoverd_stop() in release_lockspace() and the new_lockspace() error path, and wait on a new ls_kobj_done completion before freeing the lockspace or dropping the module reference, avoiding races with delayed kobject release. - Dropped v1 patch 8 (s390/sclp_mem) per Sumanth Korikkar: the /sys/firmware/memory/memoryX kobjects are permanent, so sclp_mem.c is folded into patch 9 with .release = NULL. - Patch 7 (ubifs): Add Tested-by and Reviewed-by from Zhihao Cheng. - Patch 8 (drm/amdkfd): Check q->kobj.state_in_sysfs before kobject_del() in kfd_procfs_del_queue(). - Patch 9 (kobject): Cover sclp_mem.c and the new amdgpu_ualink.c ualink_xcp_info_ktype, fix the overlay-sysfs.c comment, and prefix legacy .release = NULL comments with "Pre-existing:". - Patch 9 (kobject): The ioat, kunpeng_hccs and omapfb display comments now say that the existing teardown can use-after-free under CONFIG_DEBUG_KOBJECT_RELEASE (reported by Sashiko). Fixing those drivers is left to follow-up patches. v2: https://lore.kernel.org/all/20261027223847.652884-1-irogers@google.com/ v1: https://lore.kernel.org/all/20261013223946.1836757-1-irogers@google.com/ [1] https://lpc.events/event/20/contributions/2392/ [2] https://lore.kernel.org/lkml/20261014225811.i.852-kees@kernel.org/ [3] https://lore.kernel.org/all/DMLWX8NY1N1N.2OMQMQCIVRR18@kernel.org/ Ian Rogers (9): Compiler Attributes: Add __must_init macro powerpc/secvar: Add missing kobject release callback to secvar_ktype sh: sq: Add missing kobject release callback to ktype_percpu_entry cpufreq: governor: Initialize kobj_type release callback statically dlm: Free dlm_ls in kobject release callback xen/sys-hypervisor: Add release callback to hyp_sysfs_kobj_type ubifs: sysfs: Use kset_create_and_add() for ubifs_kset drm/amdkfd: Free queue in procfs_queue_type kobject release callback kobject: Require explicit initialization of struct kobj_type::release Documentation/conf.py | 1 + arch/arm64/kernel/cpuinfo.c | 5 ++++ arch/powerpc/kernel/secvar-sysfs.c | 6 +++++ arch/sh/kernel/cpu/sh4/sq.c | 6 +++++ drivers/acpi/sysfs.c | 2 ++ drivers/cpufreq/cpufreq_conservative.c | 5 +++- drivers/cpufreq/cpufreq_governor.c | 4 +-- drivers/cpufreq/cpufreq_governor.h | 1 + drivers/cpufreq/cpufreq_ondemand.c | 5 +++- drivers/dma/ioat/sysfs.c | 7 +++++ drivers/gpu/drm/amd/amdgpu/amdgpu_ualink.c | 5 ++++ drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c | 10 +++++++ drivers/gpu/drm/amd/amdkfd/kfd_process.c | 12 ++++++--- drivers/gpu/drm/amd/amdkfd/kfd_queue.c | 5 +++- drivers/infiniband/hw/hfi1/sysfs.c | 5 ++++ drivers/infiniband/hw/usnic/usnic_ib_sysfs.c | 5 ++++ drivers/parisc/pdc_stable.c | 5 ++++ drivers/power/supply/ab8500_fg.c | 5 ++++ drivers/s390/char/sclp_mem.c | 2 ++ drivers/soc/hisilicon/kunpeng_hccs.c | 21 +++++++++++++++ .../fbdev/omap2/omapfb/dss/display-sysfs.c | 7 +++++ .../fbdev/omap2/omapfb/dss/manager-sysfs.c | 8 ++++++ .../fbdev/omap2/omapfb/dss/overlay-sysfs.c | 8 ++++++ drivers/xen/sys-hypervisor.c | 6 +++++ fs/dlm/dlm_internal.h | 1 + fs/dlm/lockspace.c | 26 ++++++++++++++----- fs/erofs/sysfs.c | 10 +++++++ fs/f2fs/sysfs.c | 15 +++++++++++ fs/ocfs2/cluster/masklog.c | 5 ++++ fs/ubifs/sysfs.c | 24 +++++------------ include/linux/compiler_attributes.h | 12 +++++++++ include/linux/kobject.h | 2 +- scripts/checkpatch.pl | 1 + tools/lib/python/kdoc/xforms_lists.py | 1 + 34 files changed, 211 insertions(+), 32 deletions(-) base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4 -- 2.56.0.455.g6c5a503b38-goog