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auxdisplay: line-display: fix NULL dereference in linedisp_release

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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: 66c9380948 ("auxdisplay: linedisp: encapsulate container_of usage within to_linedisp")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Guangshuo Li
2026-03-27 01:14:12 +08:00
committed by Andy Shevchenko
parent 995a418a6c
commit 7f138de156
1 changed files with 1 additions and 1 deletions
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2
drivers/auxdisplay/line-display.c
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@@ -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);