• Mohammed Shafi Shajakhan's avatar
    ath10k: fix soft lockup during firmware crash/hw-restart · c2cac2f7
    Mohammed Shafi Shajakhan authored
    During firmware crash (or) user requested manual restart
    the system gets into a soft lock up state because of the
    below root cause.
    
    During user requested hardware restart / firmware crash
    the system goes into a soft lockup state as 'napi_synchronize'
    is called after 'napi_disable' (which sets 'NAPI_STATE_SCHED'
    bit) and it sleeps into infinite loop as it waits for
    'NAPI_STATE_SCHED' to be cleared. This condition is hit because
    'ath10k_hif_stop' is called twice as below (resulting in calling
    'napi_synchronize' after 'napi_disable')
    
    'ath10k_core_restart' -> 'ath10k_hif_stop' (ATH10K_STATE_ON) ->
    -> 'ieee80211_restart_hw' -> 'ath10k_start' -> 'ath10k_halt' ->
    'ath10k_core_stop' -> 'ath10k_hif_stop' (ATH10K_STATE_RESTARTING)
    
    Fix this by calling 'ath10k_halt' in ath10k_core_restart itself
    as it makes more sense before informing mac80211 to restart h/w
    Also remove 'ath10k_halt' in ath10k_start for the state of 'restarting'
    
    Fixes: 3c97f5de ("ath10k: implement NAPI support")
    Cc: <stable@vger.kernel.org> # v4.9
    Signed-off-by: default avatarMohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
    Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
    c2cac2f7
core.c 60.7 KB