From 625fdac41cfc4ca9e1774a0d31d7985aec2c1d66 Mon Sep 17 00:00:00 2001 From: Guangshuo Li Date: Fri, 27 Mar 2026 01:14:12 +0800 Subject: auxdisplay: line-display: fix NULL dereference in linedisp_release commit 7f138de156b20d9f9da6f72f90b63c01941d97d3 upstream. 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. Fixes: 66c93809487e ("auxdisplay: linedisp: encapsulate container_of usage within to_linedisp") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li Reviewed-by: Geert Uytterhoeven Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/auxdisplay/line-display.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c index 4e22373fcc1a..e80e94262830 100644 --- a/drivers/auxdisplay/line-display.c +++ b/drivers/auxdisplay/line-display.c @@ -365,7 +365,7 @@ static DEFINE_IDA(linedisp_id); static void linedisp_release(struct device *dev) { - struct linedisp *linedisp = to_linedisp(dev); + struct linedisp *linedisp = container_of(dev, struct linedisp, dev); kfree(linedisp->map); kfree(linedisp->message); -- cgit v1.2.3