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From:   gregory.greenman@intel.com
To:     johannes@sipsolutions.net
Cc:     linux-wireless@vger.kernel.org,
        Johannes Berg <johannes.berg@intel.com>,
        Gregory Greenman <gregory.greenman@intel.com>
Subject: [PATCH wireless 03/12] wifi: iwlwifi: mvm: fix cancel_delayed_work_sync() deadlock
Date:   Sun, 14 May 2023 12:15:46 +0300
Message-Id: <20230514120631.b1813c823b4d.I9d20cc06d24fa40b6774d3dd95ea5e2bf8dd015b@changeid>
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From: Johannes Berg <johannes.berg@intel.com>

Lockdep points out that we can deadlock here by calling
cancel_delayed_work_sync() because that might be already
running and gotten interrupted by the NAPI soft-IRQ.
Even just calling something that can sleep is wrong in
this context though.

Luckily, it doesn't even really matter since the things
we need to do are idempotent, so just drop the _sync().

Fixes: e5d153ec54f0 ("iwlwifi: mvm: fix CSA AP side")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index e1d02c260e69..01432274a6da 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -2512,7 +2512,7 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 				RCU_INIT_POINTER(mvm->csa_tx_blocked_vif, NULL);
 				/* Unblock BCAST / MCAST station */
 				iwl_mvm_modify_all_sta_disable_tx(mvm, mvmvif, false);
-				cancel_delayed_work_sync(&mvm->cs_tx_unblock_dwork);
+				cancel_delayed_work(&mvm->cs_tx_unblock_dwork);
 			}
 		}
 
-- 
2.38.1