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Subject: Re: [PATCH] wifi: ath12k: avoid deadlock by change
 ieee80211_queue_work
 for regd_update_work
From:   Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20230718024724.29120-1-quic_wgong@quicinc.com>
References: <20230718024724.29120-1-quic_wgong@quicinc.com>
To:     Wen Gong <quic_wgong@quicinc.com>
Cc:     <ath12k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
        <quic_wgong@quicinc.com>
User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.11.2
Message-ID: <169105439308.894438.14073090276070005288.kvalo@kernel.org>
Date:   Thu,  3 Aug 2023 09:19:54 +0000 (UTC)
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Wen Gong <quic_wgong@quicinc.com> wrote:

> Deadlock is easily happened while shutdown wlan interface such as run
> "ifconfig wlan0 down".
> 
> The reason is because when ar->regd_update_work is ran, it will
> call wiphy_lock(ar->hw->wiphy) in function ath12k_regd_update() which
> is running in workqueue of ieee80211_local queued by ieee80211_queue_work().
> Another thread from "ifconfig wlan0 down" will also accuqire the lock
> by wiphy_lock(sdata->local->hw.wiphy) in function ieee80211_stop(), and
> then it call ieee80211_stop_device() to flush_workqueue(local->workqueue),
> this will wait the workqueue of ieee80211_local finished. Then deadlock
> will happen easily if the two thread run meanwhile.
> 
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4
> 
> Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

8198950ccb7d wifi: ath12k: avoid deadlock by change ieee80211_queue_work for regd_update_work

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20230718024724.29120-1-quic_wgong@quicinc.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches