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| author | Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> | 2019-02-09 00:38:45 +0100 |
|---|---|---|
| committer | Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> | 2019-02-15 19:48:39 +0100 |
| commit | 69ef9bc54715fb1cb7786ada15774e469e822209 (patch) | |
| tree | 175415062a9d821fd89f3966a55e19431fa6e14c | |
| parent | 8834f5600cf3c8db365e18a3d5cac2c2780c81e5 (diff) | |
| download | linux-69ef9bc54715fb1cb7786ada15774e469e822209.tar.bz2 | |
auxdisplay: ht16k33: fix potential user-after-free on module unload
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>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
| -rw-r--r-- | drivers/auxdisplay/ht16k33.c | 2 |
1 files changed, 1 insertions, 1 deletions
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); |