cr: don't touch VM above TASK_SIZE.

VM above TASK_SIZE is read-only but some areas are mapped on ARM
into the process address space.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/x86/include/asm/types.h

@@ -245,4 +245,6 @@ typedef struct {
 # define MADV_DONTDUMP 16
 #endif
 
+#define TASK_SIZE ((1UL << 47) - 1)
+
 #endif /* __CR_ASM_TYPES_H__ */

parasite-syscall.c

@@ -591,6 +591,9 @@ int parasite_dump_pages_seized(struct parasite_ctl *ctl, struct list_head *vma_a
 			continue;
 		}
 
+		if (vma_area->vma.end > TASK_SIZE)
+			continue;
+
 		ret = parasite_execute(PARASITE_CMD_DUMPPAGES, ctl);
 		if (ret) {
 			pr_err("Dumping pages failed with %d\n", ret);

pie/restorer.c

@@ -466,6 +466,9 @@ long __export_restore_task(struct task_restore_core_args *args)
 			}
 		}
 
+		if (vma_entry->end >= TASK_SIZE)
+			continue;
+
 		if (vma_entry->end > premmapped_end) {
 			if (vma_entry->start < premmapped_end)
 				addr = premmapped_end;
@@ -488,6 +491,9 @@ long __export_restore_task(struct task_restore_core_args *args)
 		if (!vma_priv(vma_entry))
 			continue;
 
+		if (vma_entry->end >= TASK_SIZE)
+			continue;
+
 		if (vma_entry->start > vma_entry->shmid)
 			break;
 
@@ -505,6 +511,9 @@ long __export_restore_task(struct task_restore_core_args *args)
 		if (!vma_priv(vma_entry))
 			continue;
 
+		if (vma_entry->start > TASK_SIZE)
+			continue;
+
 		if (vma_entry->start < vma_entry->shmid)
 			break;