Forwarded: [PATCH] INFO: task hung in ieee80211_register_hw (8)

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Subject: [PATCH] INFO: task hung in ieee80211_register_hw (8)
Author: jchuang26@m.fudan.edu.cn

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git main

Reported-by: syzbot+c92af8613ad38696ff09@syzkaller.appspotmail.com

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim_main.c b/drivers/net/wireless/virtual/mac80211_hwsim_main.c
index 02b6d81cc..cef2f4b08 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim_main.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim_main.c
@@ -7150,6 +7150,13 @@ static struct genl_family hwsim_genl_family __ro_after_init = {
 	.maxattr = HWSIM_ATTR_MAX,
 	.policy = hwsim_genl_policy,
 	.netnsok = true,
+	/*
+	 * Avoid holding the global genl mutex while creating a radio,
+	 * since that takes RTNL in ieee80211_register_hw().  A task
+	 * holding RTNL and waiting for the genl mutex would otherwise
+	 * deadlock with us.
+	 */
+	.parallel_ops = true,
 	.module = THIS_MODULE,
 	.small_ops = hwsim_ops,
 	.n_small_ops = ARRAY_SIZE(hwsim_ops),