Abhishek Kumar <kuabhs@xxxxxxxxxxxx> writes:
> 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@xxxxxxxxxxx>
> Signed-off-by: Wen Gong <quic_wgong@xxxxxxxxxxx>
> Signed-off-by: Abhishek Kumar <kuabhs@xxxxxxxxxxxx>
> ---
>
> Changes in v2:
> - Fixed typo, replaced ath11k by ath10k in the comments.
> - Adjusted the position of my S-O-B tag.
> - Added the Tested-on tag.
>
> drivers/net/wireless/ath/ath10k/mac.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
> index d804e19a742a..e9c1f11fef0a 100644
> --- a/drivers/net/wireless/ath/ath10k/mac.c
> +++ b/drivers/net/wireless/ath/ath10k/mac.c
> @@ -5345,8 +5345,22 @@ static void ath10k_stop(struct ieee80211_hw *hw)
>
> 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.
> + */
> + ath10k_wait_for_suspend(ar,
> + WMI_PDEV_SUSPEND_AND_DISABLE_INTR);
> + }
I'm nitpicking but I prefer to use parenthesis with function names, so I
changed the comments. Also there was one ath10k-check warning:
drivers/net/wireless/ath/ath10k/mac.c:5360: line length of 91 exceeds 90 columns
In the pending branch I changed it to:
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);
}
Not really pretty but I prefer to keep ath10k warning free.
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