APPLIED: [SRU Xenial][v4][PATCH] UBUNTU: SAUCE: Redpine: improve cancel_hw_scan handling to fix kernel panic

[Khaled Elmously]

..to xenial master-next

On 2018-07-16 19:29:47 , Siva Rebbagondla wrote:
> From: Siva Rebbagondla <siva.rebbagondla at redpinesignals.com>
> 
> BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1773410
> BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1777850
> 
> Kernel panic is observed when network manager is stopped or Interface is
> is DOWN, while system is entering into hibernation. The root cause of the
> issue is scan work function keeps running even after cancel_hw_scan() call.
> Issue is resolved by calling cancel_work_sync().
> 
> ...skipping...
> [ 1171.913244] BUG: unable to handle page request at 00000000001067e38
> [ 1171.913248] IP: cfg80211_scan_done+0xb0/0xc0 [cfg80211]
> [ 1171.913554] Hardware name: Dell Inc. Edge Gateway 3003/      , BIOS 01.00.06 01/22/2018
> [ 1171.913668] Workqueue: phy1 ieee80211_scan_work [mac80211]
> [ 1171.913773] RIP: 0010:cfg80211_scan_done+0xb0/0xc0 [cfg80211]
> [ 1171.913780] RSP: 0018:ffffc1fe41b47dc8 EFLAGS: 00010286
> [ 1171.913789] RAX: 0000000000000001 RBX: ffffffffc0e60120 RCX: 0000000100080006
> [ 1171.913794] RDX: ffff9eeab7e3bc58 RSI: ffff9eeab0c69080 RDI: ffff9eeab7e3bc00
> [ 1171.913799] RBP: ffff9eeab7e3bc00 R08: 00000000b7e3b201 R09: 0000000100080006
> [ 1171.913805] R10: ffffc1fe41b47d20 R11: 0000000000000000 R12: ffff9eeab0c69080
> [ 1171.913810] R13: 0000000000000022 R14: ffff9eeab0c68760 R15: ffff9eeab7af3c00
> [ 1171.913817] FS:  0000000000000000(0000) GS:ffff9eeab0000000(0000) knlGS:0000000000000000
> [ 1171.913823] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1171.913828] CR2: 00007f76c73ac190 CR3: 000000006e20a000 CR4: 00000000001006f0
> [ 1171.913833] Call Trace:
> [ 1171.913864]  ? rsi_mac80211_sta_remove+0x260/0x260 [rsi_91x]
> [ 1171.913971]  __ieee80211_scan_completed+0xb1/0x390 [mac80211]
> [ 1171.914078]  ieee80211_scan_work+0x7e/0x480 [mac80211]
> [ 1171.914098]  process_one_work+0x142/0x3d0
> [ 1171.914111]  worker_thread+0x229/0x440
> [ 1171.914122]  kthread+0xf5/0x130
> [ 1171.914132]  ? process_one_work+0x3d0/0x3d0
> [ 1171.914140]  ? kthread_associate_blkcg+0x90/0x90
> [ 1171.914152]  ret_from_fork+0x35/0x40
> 
> Signed-off-by: Siva Rebbagondla <siva.rebbagondla at redpinesignals.com>
> ---
> v2: Added enhancement in case of AP mode.
> v3: Updated BugLink is in proper format.
> v4: Added enhancement for handling mutex_locks.
> ---
>  ubuntu/rsi/rsi_91x_mac80211.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/ubuntu/rsi/rsi_91x_mac80211.c b/ubuntu/rsi/rsi_91x_mac80211.c
> index 36c0cfd..727a754 100644
> --- a/ubuntu/rsi/rsi_91x_mac80211.c
> +++ b/ubuntu/rsi/rsi_91x_mac80211.c
> @@ -375,6 +375,7 @@ static int rsi_mac80211_hw_scan_start(struct ieee80211_hw *hw,
>  	if (common->bgscan_en || common->scan_in_prog)
>  		return -EBUSY;
>  
> +	cancel_work_sync(&common->scan_work);
>  	mutex_lock(&common->mutex);
>  
>  	if (!bss->assoc) {
> @@ -627,6 +628,7 @@ static void rsi_mac80211_stop(struct ieee80211_hw *hw)
>  
>  	ven_rsi_dbg(ERR_ZONE, "===> Interface DOWN <===\n");
>  
> +	cancel_work_sync(&common->scan_work);
>  	mutex_lock(&common->mutex);
>  	
>  	common->iface_down = true;
> @@ -2343,14 +2345,10 @@ void rsi_mac80211_rfkill_poll(struct ieee80211_hw *hw)
>  	struct rsi_hw *adapter = hw->priv;
>  	struct rsi_common *common = adapter->priv;
>  	
> -	mutex_lock(&common->mutex);
> -
>  	if (common->fsm_state != FSM_MAC_INIT_DONE)
>  		wiphy_rfkill_set_hw_state(hw->wiphy, true);
>  	else
>  		wiphy_rfkill_set_hw_state(hw->wiphy, false);
> -
> -	mutex_unlock(&common->mutex);
>  }
>  
>  #ifdef CONFIG_VEN_RSI_WOW
> -- 
> 2.5.5
> 
> 
> -- 
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