mm: vmalloc: pass proper vm_start into debugobjects

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.

[akpm@linux-foundation.org: fix warning]
Link: http://lkml.kernel.org/r/1523961828-9485-3-git-send-email-cpandya@codeaurora.org
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -1128,15 +1128,16 @@ 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((void *)va->va_start,
+				    (va->va_end - va->va_start));
 	free_unmap_vmap_area(va);
 }
 EXPORT_SYMBOL(vm_unmap_ram);
@@ -1511,8 +1512,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
 		return;
 	}
 
-	debug_check_no_locks_freed(addr, get_vm_area_size(area));
-	debug_check_no_obj_freed(addr, get_vm_area_size(area));
+	debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
+	debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
 
 	remove_vm_area(addr);
 	if (deallocate_pages) {