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Message-ID: <306b8f3c-55ff-24a3-1f7f-31c0b9e247fc@gmail.com>
Date:   Mon, 21 Mar 2022 12:51:16 +0100
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Subject: Re: [PATCH] ath11k: acquire ab->base_lock in unassign when finding
 the peer by addr
Content-Language: en-US
To:     Kalle Valo <kvalo@kernel.org>
Cc:     ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Carl Huang <cjhuang@codeaurora.org>
References: <20220314215253.92658-1-dossche.niels@gmail.com>
 <87zgljmvne.fsf@kernel.org>
From:   Niels Dossche <dossche.niels@gmail.com>
In-Reply-To: <87zgljmvne.fsf@kernel.org>
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On 21/03/2022 11:45, Kalle Valo wrote:
> Niels Dossche <dossche.niels@gmail.com> writes:
> 
>> ath11k_peer_find_by_addr states via lockdep that ab->base_lock must be
>> held when calling that function in order to protect the list. All
>> callers except ath11k_mac_op_unassign_vif_chanctx have that lock
>> acquired when calling ath11k_peer_find_by_addr. That lock is also not
>> transitively held by a path towards ath11k_mac_op_unassign_vif_chanctx.
>> The solution is to acquire the lock when calling
>> ath11k_peer_find_by_addr inside ath11k_mac_op_unassign_vif_chanctx.
>>
>> Fixes: 701e48a43e15 ("ath11k: add packet log support for QCA6390")
>> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
>> ---
>>  drivers/net/wireless/ath/ath11k/mac.c | 12 +++++++++---
>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
>> index 07f499d5ec92..5db2333478a2 100644
>> --- a/drivers/net/wireless/ath/ath11k/mac.c
>> +++ b/drivers/net/wireless/ath/ath11k/mac.c
>> @@ -7077,9 +7077,15 @@ ath11k_mac_op_unassign_vif_chanctx(struct ieee80211_hw *hw,
>>  	WARN_ON(!arvif->is_started);
>>  
>>  	if (ab->hw_params.vdev_start_delay &&
>> -	    arvif->vdev_type == WMI_VDEV_TYPE_MONITOR &&
>> -	    ath11k_peer_find_by_addr(ab, ar->mac_addr))
>> -		ath11k_peer_delete(ar, arvif->vdev_id, ar->mac_addr);
>> +	    arvif->vdev_type == WMI_VDEV_TYPE_MONITOR) {
>> +		struct ath11k_peer *peer;
> 
> In the pending branch I moved the declaration to the beginning of the
> function and added this to the commit log:
> 
> "I am currently working on a static analyser to detect missing locks and
> this was a reported case. I manually verified the report by looking at
> the code, but I do not have real hardware so this is compile tested
> only."
> 

Sounds good to me. Thanks!