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

[Shuah Khan]

On 2/10/21 1:13 AM, Kalle Valo wrote:
> Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxx>
>
> 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()?

Yes. I will send the patch just for ath10k_wmi_event_tdls_peer()
on top of your patch.

> 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.

thanks,
-- Shuah