[PATCH v2 2/2] mm: vmalloc: Pass proper vm_start into debugobjects

From: Chintan Pandya
Date: Tue Apr 17 2018 - 06:44:29 EST


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.

Signed-off-by: Chintan Pandya <cpandya@xxxxxxxxxxxxxx>
---
mm/vmalloc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 12d675c..033c918 100644
--- 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);
@@ -1507,8 +1507,8 @@ 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) {
--
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