Messages in this thread | | | Date | Mon, 11 Feb 2019 08:26:19 +0100 | From | Robin van der Gracht <> | Subject | Re: [PATCH] auxdisplay: ht16k33: fix potential user-after-free on module unload |
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On Sat, 9 Feb 2019 01:15:22 +0100 Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> wrote:
> On module unload/remove, we need to ensure that work does not run > after we have freed resources. Concretely, cancel_delayed_work() > may return while the callback function is still running. > > From kernel/workqueue.c: > > The work callback function may still be running on return, > unless it returns true and the work doesn't re-arm itself. > Explicitly flush or use cancel_delayed_work_sync() to wait on it. > > Link: https://lore.kernel.org/lkml/20190204220952.30761-1-TheSven73@googlemail.com/ > Reported-by: Sven Van Asbroeck <thesven73@gmail.com> > Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> > --- > drivers/auxdisplay/ht16k33.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c > index a43276c76fc6..21393ec3b9a4 100644 > --- a/drivers/auxdisplay/ht16k33.c > +++ b/drivers/auxdisplay/ht16k33.c > @@ -509,7 +509,7 @@ static int ht16k33_remove(struct i2c_client *client) > struct ht16k33_priv *priv = i2c_get_clientdata(client); > struct ht16k33_fbdev *fbdev = &priv->fbdev; > > - cancel_delayed_work(&fbdev->work); > + cancel_delayed_work_sync(&fbdev->work); > unregister_framebuffer(fbdev->info); > framebuffer_release(fbdev->info); > free_page((unsigned long) fbdev->buffer);
Looks good
Acked-by: Robin van der Gracht <robin@protonic.nl>
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