On Tue, Aug 4, 2015 at 5:55 AM, Dan Carpenter <dan.carpenter@oracle.com>
wrote:

> On Sat, Aug 01, 2015 at 01:21:09PM +0200, Julia Lawall wrote:
> > Currently, is there any documentation about when these functions can be
> > used?  All I remember seeing is a discussion of what the functions do and
> > what functions are available.  But nothing about when they should and
> > should not be used.
> >
>
> The documentation for devm_kmalloc() doesn't list common pitfalls.  The
> other big one which should be obvious, but happens often is freeing
> devm_ memory with kfree().
>
> /**
>  * devm_kmalloc - Resource-managed kmalloc
>  * @dev: Device to allocate memory for
>  * @size: Allocation size
>  * @gfp: Allocation gfp flags
>  *
>  * Managed kmalloc.  Memory allocated with this function is
>  * automatically freed on driver detach.  Like all other devres
>  * resources, guaranteed alignment is unsigned long long.
>  *
>  * RETURNS:
>  * Pointer to allocated memory on success, NULL on failure.
>  */
>

I wonder if it would be possible to note that the current thread is going
through probe() or remove() code path in driver core and scream if we
encounter devm* call outside of such path. That will give false positives
in cases when there is a legitimate mix of automatic and manual resource
management (i.e. you rely on automatic cleanup in probe()/remove() but need
to free/reallocate object somewhere else), but we can create another call
for that.

Thanks.

-- 
Dmitry