Hello Baoquan He,
This static checker warning is related to yesterdays, but more straight
forward to analyze.
The patch ae5dfc510155: "mm/vmalloc: explicitly identify vm_map_ram
area when shown in /proc/vmcoreinfo" from Jan 13, 2023, leads to the
following Smatch static checker warning:
mm/vmalloc.c:4244 s_show()
error: we previously assumed 'v' could be null (see line 4241)
mm/vmalloc.c
4226 static int s_show(struct seq_file *m, void *p)
4227 {
4228 struct vmap_area *va;
4229 struct vm_struct *v;
4230
4231 va = list_entry(p, struct vmap_area, list);
4232
4233 if (!va->vm && (va->flags & VMAP_RAM)) {
^^^^^^ ^^^^^^^^^^^^^^^^^^^^
Assume va->vm is NULL but the VMAP_RAM flag is not set.
4234 seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
4235 (void *)va->va_start, (void *)va->va_end,
4236 va->va_end - va->va_start);
4237
4238 goto final;
4239 }
4240
4241 v = va->vm;
^^^^^^^^^^
Assignment
4242
4243 seq_printf(m, "0x%pK-0x%pK %7ld",
--> 4244 v->addr, v->addr + v->size, v->size);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dead.
4245
4246 if (v->caller)
4247 seq_printf(m, " %pS", v->caller);
4248
regards,
dan carpenter
