From: Deepanshu Kartikey Date: Wed, 22 Apr 2026 14:47:34 +0000 (+0530) Subject: media: rtl2832: fix use-after-free in rtl2832_remove() X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=680daf40a82d483949f87f0d8f98639dc47e610c;p=thirdparty%2Fkernel%2Flinux.git media: rtl2832: fix use-after-free in rtl2832_remove() cancel_delayed_work_sync() is called before i2c_mux_del_adapters() in rtl2832_remove(). While the cancel waits for any running instance of i2c_gate_work to finish, it does not prevent the timer from being rescheduled by a concurrent thread. During probe, the r820t_attach() call attempts I2C transfers through the mux adapter. These transfers go through i2c_mux_master_xfer(), which calls rtl2832_deselect() after the transfer completes, rescheduling i2c_gate_work via schedule_delayed_work(). If this transfer is still in flight when rtl2832_remove() runs, rtl2832_deselect() can reschedule i2c_gate_work after it has been cancelled, causing a use-after-free when kfree(dev) is called. Fix this by calling i2c_mux_del_adapters() before cancel_delayed_work_sync(). Once the mux adapter is unregistered, no new I2C transfers can go through it, so rtl2832_deselect() can no longer reschedule i2c_gate_work. The subsequent cancel_delayed_work_sync() is then guaranteed to be final. Fixes: cddcc40b1b15 ("[media] rtl2832: convert to use an explicit i2c mux core") Cc: stable@vger.kernel.org Reported-by: syzbot+019ced393ab913002b75@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=019ced393ab913002b75 Signed-off-by: Deepanshu Kartikey Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c index d8e1546aea5e..9898f729304a 100644 --- a/drivers/media/dvb-frontends/rtl2832.c +++ b/drivers/media/dvb-frontends/rtl2832.c @@ -1115,10 +1115,10 @@ static void rtl2832_remove(struct i2c_client *client) dev_dbg(&client->dev, "\n"); - cancel_delayed_work_sync(&dev->i2c_gate_work); - i2c_mux_del_adapters(dev->muxc); + cancel_delayed_work_sync(&dev->i2c_gate_work); + regmap_exit(dev->regmap); kfree(dev);