diff options
Diffstat (limited to 'include/linux/rmap.h')
| -rw-r--r-- | include/linux/rmap.h | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index c4f4903b1088..6cd020eea37a 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -449,6 +449,28 @@ static inline void __folio_rmap_sanity_checks(const struct folio *folio, default: VM_WARN_ON_ONCE(true); } + + /* + * Anon folios must have an associated live anon_vma as long as they're + * mapped into userspace. + * Note that the atomic_read() mainly does two things: + * + * 1. In KASAN builds with CONFIG_SLUB_RCU_DEBUG, it causes KASAN to + * check that the associated anon_vma has not yet been freed (subject + * to KASAN's usual limitations). This check will pass if the + * anon_vma's refcount has already dropped to 0 but an RCU grace + * period hasn't passed since then. + * 2. If the anon_vma has not yet been freed, it checks that the + * anon_vma still has a nonzero refcount (as opposed to being in the + * middle of an RCU delay for getting freed). + */ + if (folio_test_anon(folio) && !folio_test_ksm(folio)) { + unsigned long mapping = (unsigned long)folio->mapping; + struct anon_vma *anon_vma; + + anon_vma = (void *)(mapping - FOLIO_MAPPING_ANON); + VM_WARN_ON_FOLIO(atomic_read(&anon_vma->refcount) == 0, folio); + } } /* @@ -893,7 +915,7 @@ static inline int folio_try_share_anon_rmap_pmd(struct folio *folio, * Called from mm/vmscan.c to handle paging out */ int folio_referenced(struct folio *, int is_locked, - struct mem_cgroup *memcg, unsigned long *vm_flags); + struct mem_cgroup *memcg, vm_flags_t *vm_flags); void try_to_migrate(struct folio *folio, enum ttu_flags flags); void try_to_unmap(struct folio *, enum ttu_flags flags); @@ -1025,7 +1047,7 @@ struct anon_vma *folio_lock_anon_vma_read(const struct folio *folio, static inline int folio_referenced(struct folio *folio, int is_locked, struct mem_cgroup *memcg, - unsigned long *vm_flags) + vm_flags_t *vm_flags) { *vm_flags = 0; return 0; |