The patch titled Subject: mm: take into account mm_cid size for mm_struct static definitions has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-take-into-account-mm_cid-size-for-mm_struct-static-definitions.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Mathieu Desnoyers mathieu.desnoyers@efficios.com Subject: mm: take into account mm_cid size for mm_struct static definitions Date: Wed, 24 Dec 2025 12:33:58 -0500
Both init_mm and efi_mm static definitions need to make room for the 2 mm_cid cpumasks.
This fixes possible out-of-bounds accesses to init_mm and efi_mm.
Add a space between # and define for the mm_alloc_cid() definition to make it consistent with the coding style used in the rest of this header file.
Link: https://lkml.kernel.org/r/20251224173358.647691-4-mathieu.desnoyers@efficios... Fixes: af7f588d8f73 ("sched: Introduce per-memory-map concurrency ID") Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Mark Brown broonie@kernel.org Cc: Aboorva Devarajan aboorvad@linux.ibm.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: Christan K��nig christian.koenig@amd.com Cc: Christian Brauner brauner@kernel.org Cc: Christoph Lameter cl@linux.com Cc: David Hildenbrand david@redhat.com Cc: David Rientjes rientjes@google.com Cc: Dennis Zhou dennis@kernel.org Cc: Johannes Weiner hannes@cmpxchg.org Cc: "Liam R . Howlett" liam.howlett@oracle.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Martin Liu liumartin@google.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Miaohe Lin linmiaohe@huawei.com Cc: Michal Hocko mhocko@suse.com Cc: Mike Rapoport rppt@kernel.org Cc: "Paul E. McKenney" paulmck@kernel.org Cc: Roman Gushchin roman.gushchin@linux.dev Cc: SeongJae Park sj@kernel.org Cc: Shakeel Butt shakeel.butt@linux.dev Cc: Steven Rostedt rostedt@goodmis.org Cc: Suren Baghdasaryan surenb@google.com Cc: Sweet Tea Dorminy sweettea-kernel@dorminy.me Cc: Tejun Heo tj@kernel.org Cc: Vlastimil Babka vbabka@suse.cz Cc: Wei Yang richard.weiyang@gmail.com Cc: Yu Zhao yuzhao@google.com Cc: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
include/linux/mm_types.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/include/linux/mm_types.h~mm-take-into-account-mm_cid-size-for-mm_struct-static-definitions +++ a/include/linux/mm_types.h @@ -1368,7 +1368,7 @@ extern struct mm_struct init_mm;
#define MM_STRUCT_FLEXIBLE_ARRAY_INIT \ { \ - [0 ... sizeof(cpumask_t)-1] = 0 \ + [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE - 1] = 0 \ }
/* Pointer magic because the dynamic array size confuses some compilers. */ @@ -1500,7 +1500,7 @@ static inline int mm_alloc_cid_noprof(st mm_init_cid(mm, p); return 0; } -#define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__)) +# define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__))
static inline void mm_destroy_cid(struct mm_struct *mm) { @@ -1514,6 +1514,8 @@ static inline unsigned int mm_cid_size(v return cpumask_size() + bitmap_size(num_possible_cpus()); }
+/* Use 2 * NR_CPUS as worse case for static allocation. */ +# define MM_CID_STATIC_SIZE (2 * sizeof(cpumask_t)) #else /* CONFIG_SCHED_MM_CID */ static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p) { } static inline int mm_alloc_cid(struct mm_struct *mm, struct task_struct *p) { return 0; } @@ -1522,6 +1524,7 @@ static inline unsigned int mm_cid_size(v { return 0; } +# define MM_CID_STATIC_SIZE 0 #endif /* CONFIG_SCHED_MM_CID */
struct mmu_gather; _
Patches currently in -mm which might be from mathieu.desnoyers@efficios.com are
mm-add-missing-static-initializer-for-init_mm-mm_cidlock.patch mm-rename-cpu_bitmap-field-to-flexible_array.patch mm-take-into-account-mm_cid-size-for-mm_struct-static-definitions.patch tsacct-skip-all-kernel-threads.patch lib-introduce-hierarchical-per-cpu-counters.patch mm-fix-oom-killer-inaccuracy-on-large-many-core-systems.patch mm-implement-precise-oom-killer-task-selection.patch