Re: [PATCH 2/5] ath10k: fix WARNING: suspicious RCU usage

From: Kalle Valo <kvalo@codeaurora.org>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org, ath10k@lists.infradead.org,
	Shuah Khan <skhan@linuxfoundation.org>,
	kuba@kernel.org, davem@davemloft.net
Subject: Re: [PATCH 2/5] ath10k: fix WARNING: suspicious RCU usage
Date: Wed, 10 Feb 2021 08:13:19 +0000 (UTC)	[thread overview]
Message-ID: <20210210081319.CD3FBC433C6@smtp.codeaurora.org> (raw)
In-Reply-To: <23a1333dfb0367cc69e7177a2e373df0b6d42980.1612915444.git.skhan@linuxfoundation.org>

Shuah Khan <skhan@linuxfoundation.org> wrote:

> ieee80211_find_sta_by_ifaddr() must be called under the RCU lock and
> the resulting pointer is only valid under RCU lock as well.
> 
> Fix ath10k_wmi_tlv_parse_peer_stats_info() to hold RCU lock before it
> calls ieee80211_find_sta_by_ifaddr() and release it when the resulting
> pointer is no longer needed. The log below shows the problem.
> 
> While at it, fix ath10k_wmi_tlv_op_pull_peer_stats_info() to do the same.
> 
> =============================
> WARNING: suspicious RCU usage
> 5.11.0-rc7+ #20 Tainted: G        W
> -----------------------------
> include/linux/rhashtable.h:594 suspicious rcu_dereference_check() usage!
> other info that might help us debug this:
>                rcu_scheduler_active = 2, debug_locks = 1
> no locks held by ksoftirqd/5/44.
> 
> stack backtrace:
> CPU: 5 PID: 44 Comm: ksoftirqd/5 Tainted: G        W         5.11.0-rc7+ #20
> Hardware name: LENOVO 10VGCTO1WW/3130, BIOS M1XKT45A 08/21/2019
> Call Trace:
>  dump_stack+0x7d/0x9f
>  lockdep_rcu_suspicious+0xdb/0xe5
>  __rhashtable_lookup+0x1eb/0x260 [mac80211]
>  ieee80211_find_sta_by_ifaddr+0x5b/0xc0 [mac80211]
>  ath10k_wmi_tlv_parse_peer_stats_info+0x3e/0x90 [ath10k_core]
>  ath10k_wmi_tlv_iter+0x6a/0xc0 [ath10k_core]
>  ? ath10k_wmi_tlv_op_pull_mgmt_tx_bundle_compl_ev+0xe0/0xe0 [ath10k_core]
>  ath10k_wmi_tlv_op_rx+0x5da/0xda0 [ath10k_core]
>  ? trace_hardirqs_on+0x54/0xf0
>  ? ath10k_ce_completed_recv_next+0x4e/0x60 [ath10k_core]
>  ath10k_wmi_process_rx+0x1d/0x40 [ath10k_core]
>  ath10k_htc_rx_completion_handler+0x115/0x180 [ath10k_core]
>  ath10k_pci_process_rx_cb+0x149/0x1b0 [ath10k_pci]
>  ? ath10k_htc_process_trailer+0x2d0/0x2d0 [ath10k_core]
>  ? ath10k_pci_sleep.part.0+0x6a/0x80 [ath10k_pci]
>  ath10k_pci_htc_rx_cb+0x15/0x20 [ath10k_pci]
>  ath10k_ce_per_engine_service+0x61/0x80 [ath10k_core]
>  ath10k_ce_per_engine_service_any+0x7d/0xa0 [ath10k_core]
>  ath10k_pci_napi_poll+0x48/0x120 [ath10k_pci]
>  net_rx_action+0x136/0x500
>  __do_softirq+0xc6/0x459
>  ? smpboot_thread_fn+0x2b/0x1f0
>  run_ksoftirqd+0x2b/0x60
>  smpboot_thread_fn+0x116/0x1f0
>  kthread+0x14b/0x170
>  ? smpboot_register_percpu_thread+0xe0/0xe0
>  ? __kthread_bind_mask+0x70/0x70
>  ret_from_fork+0x22/0x30
> 
> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Unlucky timing also on this one, it conflicts with a patch I applied yesterday:

https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/?h=ath-next&id=2615e3cdbd9c0e864f5906279c952a309871d225

Can you redo the patch to only change ath10k_wmi_event_tdls_peer()?

error: patch failed: drivers/net/wireless/ath/ath10k/wmi-tlv.c:240
error: drivers/net/wireless/ath/ath10k/wmi-tlv.c: patch does not apply
stg import: Diff does not apply cleanly

Patch set to Changes Requested.

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/23a1333dfb0367cc69e7177a2e373df0b6d42980.1612915444.git.skhan@linuxfoundation.org/

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

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