On Thu, Mar 6, 2025 at 10:41 AM Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > Kenneth noticed that his laptop crashes randomly when resuming from > hibernate if there is device connected and display tunneled. I was able > to reproduce this as well with the following steps: > > 1. Boot the system up, nothing connected. > 2. Connect Thunderbolt 4 dock to the host. > 3. Connect monitor to the Thunderbolt 4 dock. > 4. Verify that there is picture on the screen. > 5. Enter hibernate. > 6. Exit hibernate. > 7. Wait for the system to resume. > > Expectation: System resumes just fine, the connected monitor still > shows screen. > Actual result: There is crash during resume, screen is blank. > > What happens is that during resume from hibernate we tear down any > existing tunnels created by the boot kernel and this ends up calling > tb_dp_dprx_stop() which calls tb_tunnel_put() dropping the reference > count to zero even though we never called tb_dp_dprx_start() for it (we > never do that for discovery). This makes the discovered DP tunnel memory > to be released and any access after that causes use-after-free and > possible crash. > > Fix this so that we only stop DPRX flow if it has been started in the > first place. > > Reported-by: Kenneth Crudup <kenny@xxxxxxxxx> > Closes: https://lore.kernel.org/linux-usb/8e175721-806f-45d6-892a-bd3356af80c9@xxxxxxxxx/ > Cc: stable@xxxxxxxxxxxxxxx > Fixes: d6d458d42e1e ("thunderbolt: Handle DisplayPort tunnel activation asynchronously") > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > --- Reviewed-by: Yehezkel Bernat <YehezkelShB@xxxxxxxxx>
