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

[Chintan Pandya]

On 5/4/2018 3:12 AM, Andrew Morton wrote:
> On Tue, 17 Apr 2018 16:13:48 +0530 Chintan Pandya <cpandya@xxxxxxxxxxxxxx> 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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