On 5/4/2018 3:12 AM, Andrew Morton wrote:
On Tue, 17 Apr 2018 16:13:48 +0530 Chintan Pandya <[email protected]> 
wrote:

Client can call vunmap with some intermediate 'addr'
which may not be the start of the VM area. Entire
unmap code works with vm->vm_start which is proper
but debug object API is called with 'addr'. This
could be a problem within debug objects.

Pass proper start address into debug object API.

--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1124,15 +1124,15 @@ void vm_unmap_ram(const void *mem, unsigned int count)
        BUG_ON(addr > VMALLOC_END);
        BUG_ON(!PAGE_ALIGNED(addr));
- debug_check_no_locks_freed(mem, size);
-
        if (likely(count <= VMAP_MAX_ALLOC)) {
+               debug_check_no_locks_freed(mem, size);
                vb_free(mem, size);
                return;
        }
va = find_vmap_area(addr);
        BUG_ON(!va);
+       debug_check_no_locks_freed(va->va_start, (va->va_end - va->va_start));
        free_unmap_vmap_area(va);
  }
  EXPORT_SYMBOL(vm_unmap_ram);

hm, how did this sneak through?
My bad. I had tested them but missed bringing these compile fixes to the
patch file. Will be careful next time.


mm/vmalloc.c:1139:29: warning: passing argument 1 of debug_check_no_locks_freed 
makes pointer from integer without a cast [-Wint-conversion]
   debug_check_no_locks_freed(va->va_start, (va->va_end - va->va_start));

--- a/mm/vmalloc.c~mm-vmalloc-pass-proper-vm_start-into-debugobjects-fix
+++ a/mm/vmalloc.c
@@ -1136,7 +1136,8 @@ void vm_unmap_ram(const void *mem, unsig
va = find_vmap_area(addr);
        BUG_ON(!va);
-       debug_check_no_locks_freed(va->va_start, (va->va_end - va->va_start));
+       debug_check_no_locks_freed((void *)va->va_start,
+                                   (va->va_end - va->va_start));
        free_unmap_vmap_area(va);
  }
  EXPORT_SYMBOL(vm_unmap_ram);


Chintan
--
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