mm: take into account mm_cid size for mm_struct static definitions

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/[e-mail]
Fixes: af7f588d8f73 ("sched: Introduce per-memory-map concurrency ID")
Signed-off-by: Mathieu Desnoyers <[e-mail]>
Reviewed-by: Thomas Gleixner <[e-mail]>
Cc: Mark Brown <[e-mail]>
Cc: Aboorva Devarajan <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: Baolin Wang <[e-mail]>
Cc: Christan König <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Dennis Zhou <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: "Liam R . Howlett" <[e-mail]>
Cc: Lorenzo Stoakes <[e-mail]>
Cc: Martin Liu <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Mateusz Guzik <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Miaohe Lin <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: "Paul E. McKenney" <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Cc: SeongJae Park <[e-mail]>
Cc: Shakeel Butt <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Suren Baghdasaryan <[e-mail]>
Cc: Sweet Tea Dorminy <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Yu Zhao <[e-mail]>
Cc: Peter Zijlstra (Intel) <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/mm_types.h

···
 
 #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. */
···
 	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)
 {
···
 	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; }
···
 {
 	return 0;
 }
+# define MM_CID_STATIC_SIZE	0
 #endif /* CONFIG_SCHED_MM_CID */
 
 struct mmu_gather;