usb: typec: ucsi: split connector lock classes

Lockdep detects a possible recursive locking scenario during
ucsi init:

[    5.418616] ============================================
[    5.418634] WARNING: possible recursive locking detected
[    5.418706] --------------------------------------------
[    5.418725] kworker/4:1/82 is trying to acquire lock:
[    5.418759] ffff888119a34648 (&con->lock){+.+.}-{3:3}, at: ucsi_init_work+0x1a78/0x2eb0 [typec_ucsi]
[    5.418801]
               but task is already holding lock:
[    5.418835] ffff888119a34080 (&con->lock){+.+.}-{3:3}, at: ucsi_init_work+0x1a78/0x2eb0 [typec_ucsi]
[    5.418884]
               other info that might help us debug this:
[    5.418904]  Possible unsafe locking scenario:

[    5.418937]        CPU0
[    5.418956]        ----
[    5.418991]   lock(&con->lock);
[    5.419013]   lock(&con->lock);
[    5.419033]
                *** DEADLOCK ***

[    5.419387] Call Trace:
[    5.419406]  <TASK>
[    5.419425]  dump_stack_lvl+0x61/0xa0
[    5.419448]  print_deadlock_bug+0x4a6/0x650
[    5.419483]  __lock_acquire+0x62b6/0x7f50
[    5.419507]  lock_acquire+0x11b/0x390
[    5.419654]  __mutex_lock+0xbc/0xcd0
[    5.419741]  ucsi_init_work+0x1a78/0x2eb0
[    5.419785]  ? worker_thread+0xf53/0x2bc0
[    5.419819]  worker_thread+0xff4/0x2bc0
[    5.419842]  kthread+0x2a7/0x330
[    5.419863]  ? __pfx_worker_thread+0x10/0x10
[    5.419896]  ? __pfx_kthread+0x10/0x10
[    5.419916]  ret_from_fork+0x38/0x70
[    5.419936]  ? __pfx_kthread+0x10/0x10
[    5.419969]  ret_from_fork_asm+0x1b/0x30
[    5.419991]  </TASK>
[    5.420009] ---[ end trace 0000000000000000 ]---

The problem is that all connector locks belong to the same
lockdep lock class, so the following loop:

	for (i = 0; i < ucsi->cap.num_connectors; i++)
		ucsi_register_port(connector[i])
			mutex_lock(&connector[i]->lock)

looks like a recursive acquire of the same mutex.  Put each connector
lock into a dedicated lock class so that lockdep doesn't see it as a
possible recursion.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260515060042.136083-1-senozhatsky@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 5b7ad9e99cb949af0b769373a6993448173a43f9..43da7512dea0608d96db8d930b71b975f8588006 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1642,6 +1642,7 @@ static int ucsi_register_port(struct ucsi *ucsi, struct ucsi_connector *con)
        INIT_WORK(&con->work, ucsi_handle_connector_change);
        init_completion(&con->complete);
        mutex_init(&con->lock);
+       lockdep_set_class(&con->lock, &con->lock_key);
        INIT_LIST_HEAD(&con->partner_tasks);
        con->ucsi = ucsi;
 
@@ -1887,6 +1888,9 @@ static int ucsi_init(struct ucsi *ucsi)
                goto err_reset;
        }
 
+       for (i = 0; i < ucsi->cap.num_connectors; i++)
+               lockdep_register_key(&connector[i].lock_key);
+
        /* Register all connectors */
        for (i = 0; i < ucsi->cap.num_connectors; i++) {
                connector[i].num = i + 1;
@@ -1916,6 +1920,9 @@ static int ucsi_init(struct ucsi *ucsi)
        return 0;
 
 err_unregister:
+       for (i = 0; i < ucsi->cap.num_connectors; i++)
+               lockdep_unregister_key(&connector[i].lock_key);
+
        for (con = connector; con->port; con++) {
                if (con->wq)
                        destroy_workqueue(con->wq);
@@ -2166,6 +2173,7 @@ void ucsi_unregister(struct ucsi *ucsi)
                usb_power_delivery_unregister(ucsi->connector[i].pd);
                ucsi->connector[i].pd = NULL;
                typec_unregister_port(ucsi->connector[i].port);
+               lockdep_unregister_key(&ucsi->connector[i].lock_key);
        }
 
        kfree(ucsi->connector);

diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index cff9ddc2ae215757ca5ce558da02b98d8bc56612..51f6c3c0d36537bb83831908a779ff6fd4cd9420 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -517,6 +517,7 @@ struct ucsi_connector {
 
        struct ucsi *ucsi;
        struct mutex lock; /* port lock */
+       struct lock_class_key lock_key;
        struct work_struct work;
        struct completion complete;
        struct workqueue_struct *wq;