Re: [PATCH] auxdisplay: line-display: fix NULL dereference in linedisp_release

[Andy Shevchenko]

On Fri, Mar 27, 2026 at 01:14:12AM +0800, Guangshuo Li wrote:
> linedisp_release() currently retrieves the enclosing struct linedisp via
> to_linedisp(). That lookup depends on the attachment list, but the
> attachment may already have been removed before put_device() invokes the
> release callback. This can happen in linedisp_unregister(), and can also
> be reached from some linedisp_register() error paths.
> 
> In that case, to_linedisp() returns NULL and linedisp_release()
> dereferences it while freeing the display resources.
> 
> The struct device released here is the embedded linedisp->dev used by
> linedisp_register(), so retrieve the enclosing object directly with
> container_of() instead.

Makes sense to me. How did you find the issue?

Geert, do you agree with this change?

-- 
With Best Regards,
Andy Shevchenko