Diffstat (limited to 'ipc/util.h')
1 files changed, 13 insertions, 0 deletions
diff --git a/ipc/util.h b/ipc/util.h
index 59d78aa94987..d05b7085a887 100644
@@ -185,6 +185,19 @@ static inline void ipc_unlock(struct kern_ipc_perm *perm)
+ * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
+ * where the respective ipc_ids.rwsem is not being held down.
+ * Checks whether the ipc object is still around or if it's gone already, as
+ * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
+ * Needs to be called with kern_ipc_perm.lock held -- exception made for one
+ * checkpoint case at sys_semtimedop() as noted in code commentary.
+static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
+ return perm->deleted == 0;
struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
struct ipc_ops *ops, struct ipc_params *params);