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Subject: Re: [PATCH] wifi: ath12k: add rcu lock for ath12k_wmi_p2p_noa_event()
From: Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20240223054505.438839-1-quic_kangyang@quicinc.com>
References: <20240223054505.438839-1-quic_kangyang@quicinc.com>
To: Kang Yang <quic_kangyang@quicinc.com>
Cc: <ath12k@lists.infradead.org>, <linux-wireless@vger.kernel.org>,
 <quic_kangyang@quicinc.com>
User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.11.2
Message-ID: <170912924605.3989537.2614593152654573809.kvalo@kernel.org>
Date: Wed, 28 Feb 2024 14:07:27 +0000 (UTC)

Kang Yang <quic_kangyang@quicinc.com> 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>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

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

ee3b63586b30 wifi: ath12k: add rcu lock for ath12k_wmi_p2p_noa_event()

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20240223054505.438839-1-quic_kangyang@quicinc.com/

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