Messages in this thread | | | Subject | Re: mwifiex: Fix possible ABBA deadlock | From | Kalle Valo <> | Date | Wed, 8 Dec 2021 18:38:48 +0000 (UTC) |
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Brian Norris <briannorris@chromium.org> wrote:
> Quoting Jia-Ju Bai <baijiaju1990@gmail.com>: > > mwifiex_dequeue_tx_packet() > spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 1432 (Lock A) > mwifiex_send_addba() > spin_lock_bh(&priv->sta_list_spinlock); --> Line 608 (Lock B) > > mwifiex_process_sta_tx_pause() > spin_lock_bh(&priv->sta_list_spinlock); --> Line 398 (Lock B) > mwifiex_update_ralist_tx_pause() > spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 941 (Lock A) > > Similar report for mwifiex_process_uap_tx_pause(). > > While the locking expectations in this driver are a bit unclear, the > Fixed commit only intended to protect the sta_ptr, so we can drop the > lock as soon as we're done with it. > > IIUC, this deadlock cannot actually happen, because command event > processing (which calls mwifiex_process_sta_tx_pause()) is > sequentialized with TX packet processing (e.g., > mwifiex_dequeue_tx_packet()) via the main loop (mwifiex_main_process()). > But it's good not to leave this potential issue lurking. > > Fixes: f0f7c2275fb9 ("mwifiex: minor cleanups w/ sta_list_spinlock in cfg80211.c") > Cc: Douglas Anderson <dianders@chromium.org> > Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> > Link: https://lore.kernel.org/linux-wireless/0e495b14-efbb-e0da-37bd-af6bd677ee2c@gmail.com/ > Signed-off-by: Brian Norris <briannorris@chromium.org> > Reviewed-by: Douglas Anderson <dianders@chromium.org>
Patch applied to wireless-drivers-next.git, thanks.
1b8bb8919ef8 mwifiex: Fix possible ABBA deadlock
-- https://patchwork.kernel.org/project/linux-wireless/patch/YaV0pllJ5p/EuUat@google.com/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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