Re: [syzbot] Re: [syzbot] [net?] possible deadlock in team_device_event (3)

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Subject: Re: [syzbot] [net?] possible deadlock in team_device_event (3)
Author: aha310510@xxxxxxxxx

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master 

---
 drivers/net/team/team_core.c | 5 ++++-
 include/linux/if_team.h      | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index ab1935a4aa2c..963c8311694f 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -1621,6 +1621,7 @@ static int team_init(struct net_device *dev)
 	team->dev = dev;
 	team_set_no_mode(team);
 	team->notifier_ctx = false;
+	team->nested_depth = 1;
 
 	team->pcpu_stats = netdev_alloc_pcpu_stats(struct team_pcpu_stats);
 	if (!team->pcpu_stats)
@@ -2947,8 +2948,10 @@ static void team_port_change_check(struct team_port *port, bool linkup)
 {
 	struct team *team = port->team;
 
-	mutex_lock(&team->lock);
+	mutex_lock_nested(&team->lock, team->nested_depth);
+	team->nested_depth++;
 	__team_port_change_check(port, linkup);
+	team->nested_depth--;
 	mutex_unlock(&team->lock);
 }
 
diff --git a/include/linux/if_team.h b/include/linux/if_team.h
index cdc684e04a2f..f8b4e3ed4b44 100644
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -225,6 +225,7 @@ struct team {
 	} mcast_rejoin;
 	struct lock_class_key team_lock_key;
 	long mode_priv[TEAM_MODE_PRIV_LONGS];
+	unsigned int nested_depth;
 };
 
 static inline int team_dev_queue_xmit(struct team *team, struct team_port *port,
--