[PATCH v4 1/2] wifi: ath11k: move update channel list from update reg worker to reg notifier

[Kalle Valo]

Kang Yang <quic_kangyang at quicinc.com> writes:

> From: Wen Gong <quic_wgong at quicinc.com>
>
> Currently when ath11k gets new channel list, it will mainly do two things
> in ath11k_regd_update():
> 1. update channel list to cfg80211 by reg_work.
> 2. update cfg80211's channel list to firmware by
> ath11k_reg_update_chan_list().
>
> Flow:
> ath11k_regd_update
> ->regulatory_set_wiphy_regd
>         -> schedule_work(&reg_work)
>                 ->reg_work->reg_process_self_managed_hint
>                         ->handle_band_custom(update to cfg80211)
> -> ath11k_reg_update_chan_list(update to firmware)
>
> But ath11k_reg_update_chan_list() is immediately called after reg_work
> is queued. They are running in different threads. At this time,
> ath11k_reg_update_chan_list() may use a wrong channel list because
> handle_band_custom() may not be finished.
> This may result in out-of-bounds write errors:
> BUG: KASAN: slab-out-of-bounds in ath11k_reg_update_chan_list
> Call Trace:
>     ath11k_reg_update_chan_list+0xbfe/0xfe0 [ath11k]
>     kfree+0x109/0x3a0
>     ath11k_regd_update+0x1cf/0x350 [ath11k]
>     ath11k_regd_update_work+0x14/0x20 [ath11k]
>     process_one_work+0xe35/0x14c0
>
> So should make sure ath11k_reg_update_chan_list() is called after
> handle_band_custom() is finished.
>
> reg_process_self_managed_hint() will call reg_call_notifier() after
> handle_band_custom(). This function will call ath11k_reg_notifier(), so
> move ath11k_reg_update_chan_list() to ath11k_reg_notifier(). Then
> ath11k can update correct channel list to firmware.
>
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3
>
> Fixes: f45cb6b29cd3 ("wifi: ath11k: avoid deadlock during regulatory update in ath11k_regd_update()")
> Signed-off-by: Wen Gong <quic_wgong at quicinc.com>
> Signed-off-by: Kang Yang <quic_kangyang at quicinc.com>

I think the commit message should be completely rewritten, the idea here
is not to list functions and their call orders.

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