[openwrt/openwrt] realtek: dsa: rtl83xx: flush scheduled work on removal
LEDE Commits
lede-commits at lists.infradead.org
Thu Aug 7 08:30:35 PDT 2025
hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/feec7cf34d27e3492f90d13c934c4a0c3b3df633
commit feec7cf34d27e3492f90d13c934c4a0c3b3df633
Author: Issam Hamdi <ih at simonwunderlich.de>
AuthorDate: Thu Feb 20 16:06:00 2025 +0100
realtek: dsa: rtl83xx: flush scheduled work on removal
The workqueue items don't need to be processed directly when they are
scheduled. It can happen that they are simply processed at a much later
time. It is therefore necessary to ensure that all workqueue items of a
driver are no longer being processed before the driver (or structures of
this driver) are destroyed.
When skipping this step, the driver driver can cause a kernel Oops on
reboot.
Unfortunately, it is not recommended [1] to flush items out of the system
workqueue - simply because this can cause deadlocks. The driver itself must
have a private workqueue which is then flushed.
[1] https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
Signed-off-by: Issam Hamdi <ih at simonwunderlich.de>
Signed-off-by: Harshal Gohel <hg at simonwunderlich.de>
Signed-off-by: Sharadanand Karanjkar <sk at simonwunderlich.de>
Link: https://github.com/openwrt/openwrt/pull/19570
Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
.../files-6.12/drivers/net/dsa/rtl83xx/common.c | 37 ++++++++++++++++++++--
.../files-6.12/drivers/net/dsa/rtl83xx/dsa.c | 6 ++--
.../files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h | 1 +
3 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/common.c b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/common.c
index 7f96bdd82d..069faf7ed9 100644
--- a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/common.c
+++ b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/common.c
@@ -1330,7 +1330,7 @@ static int rtl83xx_netevent_event(struct notifier_block *this,
pr_debug("%s: updating neighbour on port %d, mac %016llx\n",
__func__, port, net_work->mac);
- schedule_work(&net_work->work);
+ queue_work(priv->wq, &net_work->work);
if (err)
netdev_warn(dev, "failed to handle neigh update (err %d)\n", err);
break;
@@ -1452,7 +1452,7 @@ static int rtl83xx_fib_event(struct notifier_block *this, unsigned long event, v
break;
}
- schedule_work(&fib_work->work);
+ queue_work(priv->wq, &fib_work->work);
return NOTIFY_DONE;
}
@@ -1486,6 +1486,7 @@ static int __init rtl83xx_sw_probe(struct platform_device *pdev)
priv->ds->ops = &rtl83xx_switch_ops;
priv->ds->needs_standalone_vlan_filtering = true;
priv->dev = dev;
+ dev_set_drvdata(dev, priv);
err = devm_mutex_init(dev, &priv->reg_mutex);
if (err)
@@ -1583,10 +1584,16 @@ static int __init rtl83xx_sw_probe(struct platform_device *pdev)
return err;
}
+ priv->wq = create_singlethread_workqueue("rtl83xx");
+ if (!priv->wq) {
+ dev_err(dev, "Error creating workqueue: %d\n", err);
+ return -ENOMEM;
+ }
+
err = dsa_register_switch(priv->ds);
if (err) {
dev_err(dev, "Error registering switch: %d\n", err);
- return err;
+ goto err_register_switch;
}
/* dsa_to_port returns dsa_port from the port list in
@@ -1694,13 +1701,37 @@ err_register_fib_nb:
err_register_ne_nb:
unregister_netdevice_notifier(&priv->nb);
err_register_nb:
+ dsa_switch_shutdown(priv->ds);
+err_register_switch:
+ destroy_workqueue(priv->wq);
+
return err;
}
static void rtl83xx_sw_remove(struct platform_device *pdev)
{
+ struct rtl838x_switch_priv *priv = platform_get_drvdata(pdev);
+
+ if (!priv)
+ return;
+
/* TODO: */
pr_debug("Removing platform driver for rtl83xx-sw\n");
+
+ /* unregister notifiers which will create workqueue entries with
+ * references to the switch structures. Also stop self-arming delayed
+ * work items to avoid them still accessing the DSA structures
+ * when they are getting shut down.
+ */
+ unregister_fib_notifier(&init_net, &priv->fib_nb);
+ unregister_netevent_notifier(&priv->ne_nb);
+ cancel_delayed_work_sync(&priv->counters_work);
+
+ dsa_switch_shutdown(priv->ds);
+
+ destroy_workqueue(priv->wq);
+
+ dev_set_drvdata(&pdev->dev, NULL);
}
static const struct of_device_id rtl83xx_switch_of_ids[] = {
diff --git a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c
index a14b502cf1..17a8b46f0c 100644
--- a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c
+++ b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c
@@ -1236,7 +1236,8 @@ static void rtldsa_poll_counters(struct work_struct *work)
spin_unlock(&counters->lock);
}
- schedule_delayed_work(&priv->counters_work, RTLDSA_COUNTERS_POLL_INTERVAL);
+ queue_delayed_work(priv->wq, &priv->counters_work,
+ RTLDSA_COUNTERS_POLL_INTERVAL);
}
static void rtldsa_init_counters(struct rtl838x_switch_priv *priv)
@@ -1254,7 +1255,8 @@ static void rtldsa_init_counters(struct rtl838x_switch_priv *priv)
}
INIT_DELAYED_WORK(&priv->counters_work, rtldsa_poll_counters);
- schedule_delayed_work(&priv->counters_work, RTLDSA_COUNTERS_POLL_INTERVAL);
+ queue_delayed_work(priv->wq, &priv->counters_work,
+ RTLDSA_COUNTERS_POLL_INTERVAL);
}
static void rtldsa_get_strings(struct dsa_switch *ds,
diff --git a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h
index 896e9ab24b..18405bdc02 100644
--- a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h
+++ b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h
@@ -1143,6 +1143,7 @@ struct rtl838x_switch_priv {
u32 lag_primary[MAX_LAGS];
u32 is_lagmember[57];
u64 lagmembers;
+ struct workqueue_struct *wq;
struct notifier_block nb; /* TODO: change to different name */
struct notifier_block ne_nb;
struct notifier_block fib_nb;
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