7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sven Peter commit 419fa32fa5bc2d7fb9d0d15d5630b1c1090808b3 upstream. tb_dp_dprx_work() checks ->dprx_canceled before it takes tb->lock so it misses a tb_dp_dprx_stop() that could not cancel the already running work. It then polls the DPRX capabilities and runs the callback for a tunnel that has already been torn down while the domain is suspending or going away. This can be hit by cancelling the DPRX read from outside the ordered tb->wq: During suspend tb_disconnect_and_release_dp() does just this and with a later patch tb_stop() will do it as well. The latter in combination with the Apple NHI where the DPRX read never completed is how I hit this. Check the flag with tb->lock held instead and check it again in tb_dp_tunnel_active() because the callback runs after the lock has been dropped again. Also clear the flag in tb_dp_dprx_start() so that it only ever describes the work that is currently in flight. Fixes: d6d458d42e1e ("thunderbolt: Handle DisplayPort tunnel activation asynchronously") Cc: stable@vger.kernel.org Signed-off-by: Sven Peter Signed-off-by: Mika Westerberg Signed-off-by: Greg Kroah-Hartman --- drivers/thunderbolt/tb.c | 12 ++++++++++++ drivers/thunderbolt/tunnel.c | 11 +++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-) --- a/drivers/thunderbolt/tb.c +++ b/drivers/thunderbolt/tb.c @@ -1912,6 +1912,18 @@ static void tb_dp_tunnel_active(struct t struct tb *tb = data; mutex_lock(&tb->lock); + + /* + * If the DPRX read was canceled the tunnel is already being torn + * down by whoever canceled it. Do not touch the adapters here + * because the routers may be gone by now. + */ + if (tunnel->dprx_canceled) { + tb_tunnel_dbg(tunnel, "DPRX read canceled, not activating\n"); + mutex_unlock(&tb->lock); + return; + } + if (tb_tunnel_is_active(tunnel)) { int consumed_up, consumed_down, ret; --- a/drivers/thunderbolt/tunnel.c +++ b/drivers/thunderbolt/tunnel.c @@ -1091,8 +1091,14 @@ static void tb_dp_dprx_work(struct work_ struct tb_tunnel *tunnel = container_of(work, typeof(*tunnel), dprx_work.work); struct tb *tb = tunnel->tb; + /* + * The DPRX read can be canceled while this work is waiting for + * tb->lock. Check the flag only once it is held: while the lock is + * held the tunnel cannot be torn down under us and the adapters are + * safe to access. + */ + mutex_lock(&tb->lock); if (!tunnel->dprx_canceled) { - mutex_lock(&tb->lock); if (tb_dp_is_usb4(tunnel->src_port->sw) && tb_dp_wait_dprx(tunnel, TB_DPRX_WAIT_TIMEOUT)) { if (ktime_before(ktime_get(), tunnel->dprx_timeout)) { @@ -1104,8 +1110,8 @@ static void tb_dp_dprx_work(struct work_ } else { tb_tunnel_set_active(tunnel, true); } - mutex_unlock(&tb->lock); } + mutex_unlock(&tb->lock); tunnel->callback(tunnel, tunnel->callback_data); tb_tunnel_put(tunnel); @@ -1122,6 +1128,7 @@ static int tb_dp_dprx_start(struct tb_tu tb_domain_get(tunnel->tb); tunnel->dprx_started = true; + tunnel->dprx_canceled = false; tunnel->dprx_timeout = dprx_timeout_to_ktime(dprx_timeout); queue_delayed_work(tunnel->tb->wq, &tunnel->dprx_work, 0);