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    Subject[PATCH AUTOSEL 5.17 056/135] ath10k: skip ath10k_halt during suspend for driver state RESTARTING
    Date
    From: Abhishek Kumar <kuabhs@chromium.org>

    [ Upstream commit b72a4aff947ba807177bdabb43debaf2c66bee05 ]

    Double free crash is observed when FW recovery(caused by wmi
    timeout/crash) is followed by immediate suspend event. The FW recovery
    is triggered by ath10k_core_restart() which calls driver clean up via
    ath10k_halt(). When the suspend event occurs between the FW recovery,
    the restart worker thread is put into frozen state until suspend completes.
    The suspend event triggers ath10k_stop() which again triggers ath10k_halt()
    The double invocation of ath10k_halt() causes ath10k_htt_rx_free() to be
    called twice(Note: ath10k_htt_rx_alloc was not called by restart worker
    thread because of its frozen state), causing the crash.

    To fix this, during the suspend flow, skip call to ath10k_halt() in
    ath10k_stop() when the current driver state is ATH10K_STATE_RESTARTING.
    Also, for driver state ATH10K_STATE_RESTARTING, call
    ath10k_wait_for_suspend() in ath10k_stop(). This is because call to
    ath10k_wait_for_suspend() is skipped later in
    [ath10k_halt() > ath10k_core_stop()] for the driver state
    ATH10K_STATE_RESTARTING.

    The frozen restart worker thread will be cancelled during resume when the
    device comes out of suspend.

    Below is the crash stack for reference:

    [ 428.469167] ------------[ cut here ]------------
    [ 428.469180] kernel BUG at mm/slub.c:4150!
    [ 428.469193] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
    [ 428.469219] Workqueue: events_unbound async_run_entry_fn
    [ 428.469230] RIP: 0010:kfree+0x319/0x31b
    [ 428.469241] RSP: 0018:ffffa1fac015fc30 EFLAGS: 00010246
    [ 428.469247] RAX: ffffedb10419d108 RBX: ffff8c05262b0000
    [ 428.469252] RDX: ffff8c04a8c07000 RSI: 0000000000000000
    [ 428.469256] RBP: ffffa1fac015fc78 R08: 0000000000000000
    [ 428.469276] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [ 428.469285] Call Trace:
    [ 428.469295] ? dma_free_attrs+0x5f/0x7d
    [ 428.469320] ath10k_core_stop+0x5b/0x6f
    [ 428.469336] ath10k_halt+0x126/0x177
    [ 428.469352] ath10k_stop+0x41/0x7e
    [ 428.469387] drv_stop+0x88/0x10e
    [ 428.469410] __ieee80211_suspend+0x297/0x411
    [ 428.469441] rdev_suspend+0x6e/0xd0
    [ 428.469462] wiphy_suspend+0xb1/0x105
    [ 428.469483] ? name_show+0x2d/0x2d
    [ 428.469490] dpm_run_callback+0x8c/0x126
    [ 428.469511] ? name_show+0x2d/0x2d
    [ 428.469517] __device_suspend+0x2e7/0x41b
    [ 428.469523] async_suspend+0x1f/0x93
    [ 428.469529] async_run_entry_fn+0x3d/0xd1
    [ 428.469535] process_one_work+0x1b1/0x329
    [ 428.469541] worker_thread+0x213/0x372
    [ 428.469547] kthread+0x150/0x15f
    [ 428.469552] ? pr_cont_work+0x58/0x58
    [ 428.469558] ? kthread_blkcg+0x31/0x31

    Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00288-QCARMSWPZ-1
    Co-developed-by: Wen Gong <quic_wgong@quicinc.com>
    Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
    Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
    Reviewed-by: Brian Norris <briannorris@chromium.org>
    Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
    Link: https://lore.kernel.org/r/20220426221859.v2.1.I650b809482e1af8d0156ed88b5dc2677a0711d46@changeid
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/net/wireless/ath/ath10k/mac.c | 20 ++++++++++++++++++--
    1 file changed, 18 insertions(+), 2 deletions(-)

    diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
    index b11aaee8b8c0..a11b31191d5a 100644
    --- a/drivers/net/wireless/ath/ath10k/mac.c
    +++ b/drivers/net/wireless/ath/ath10k/mac.c
    @@ -5339,13 +5339,29 @@ static int ath10k_start(struct ieee80211_hw *hw)
    static void ath10k_stop(struct ieee80211_hw *hw)
    {
    struct ath10k *ar = hw->priv;
    + u32 opt;

    ath10k_drain_tx(ar);

    mutex_lock(&ar->conf_mutex);
    if (ar->state != ATH10K_STATE_OFF) {
    - if (!ar->hw_rfkill_on)
    - ath10k_halt(ar);
    + if (!ar->hw_rfkill_on) {
    + /* If the current driver state is RESTARTING but not yet
    + * fully RESTARTED because of incoming suspend event,
    + * then ath10k_halt() is already called via
    + * ath10k_core_restart() and should not be called here.
    + */
    + if (ar->state != ATH10K_STATE_RESTARTING) {
    + ath10k_halt(ar);
    + } else {
    + /* Suspending here, because when in RESTARTING
    + * state, ath10k_core_stop() skips
    + * ath10k_wait_for_suspend().
    + */
    + opt = WMI_PDEV_SUSPEND_AND_DISABLE_INTR;
    + ath10k_wait_for_suspend(ar, opt);
    + }
    + }
    ar->state = ATH10K_STATE_OFF;
    }
    mutex_unlock(&ar->conf_mutex);
    --
    2.35.1
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