Received-SPF: pass (google.com: domain of linux-wireless+bounces-3970-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Message-ID: <f9e4b895-cf77-49a9-951b-05118ff5f633@quicinc.com>
Date: Fri, 23 Feb 2024 10:10:59 -0800
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] wifi: ath12k: add rcu lock for ath12k_wmi_p2p_noa_event()
Content-Language: en-US
To: Kang Yang <quic_kangyang@quicinc.com>, <ath12k@lists.infradead.org>
CC: <linux-wireless@vger.kernel.org>
References: <20240223054505.438839-1-quic_kangyang@quicinc.com>
From: Jeff Johnson <quic_jjohnson@quicinc.com>
In-Reply-To: <20240223054505.438839-1-quic_kangyang@quicinc.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit

On 2/22/2024 9:45 PM, Kang Yang wrote:
> Warning will appear when running P2P GO:
> 
> WARNING: suspicious RCU usage
> drivers/net/wireless/ath/ath12k/mac.c:583 suspicious rcu_dereference_check() usage!
> other info that might help us debug this:
> rcu_scheduler_active = 2, debug_locks = 1
> no locks held by swapper/0/0.
> stack backtrace:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.0-rc4-wt-ath+ #4
> Call Trace:
>  <IRQ>
>  dump_stack_lvl+0x82/0xa0
>  dump_stack+0x14/0x20
>  lockdep_rcu_suspicious+0x214/0x3b0
>  ath12k_mac_get_ar_by_vdev_id+0x192/0x220 [ath12k]
>  ath12k_wmi_op_rx+0x2d7/0x1b40 [ath12k]
> 
> ath12k_mac_get_ar_by_vdev_id() requires its callers to have called
> rcu_read_lock(), but in ath12k_wmi_p2p_noa_event() it is called without
> doing so, and hence the warning was triggered.
> 
> Add rcu_read_lock() and rcu_read_unlock() to avoid warning.
> 
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Fixes: 9411eecb60cb ("wifi: ath12k: implement handling of P2P NoA event")
> Reported-by: Kalle Valo <quic_kvalo@quicinc.com>
> Closes: https://lore.kernel.org/linux-wireless/87o7cusyvw.fsf@kernel.org/
> Signed-off-by: Kang Yang <quic_kangyang@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>