tree cf7c8d38ae0095a80a301b77bda32ef19da54974
parent 2dcddb598ad6ad588c281363dd13e8a2dcd553c8
author Alice Ou <alice.ou@mediatek.com> 1510622409 +0800
committer ZD Hu <zd.hu@mediatek.com> 1511265507 +0800

[WCNCR00158507] misc: Fix function callback panic for USB disconnected

[Description]
Fix reg_notifier callback panic after USB disconnected
1. After USB disconnected, WiFi driver has called wlanRemove()
   to release resources. But sometimes kernel calls mtk_reg_notify
   after that and causes kernel panic.
2. Add a g_u4HaltFlag checker to avoid that case.
3. Problem log:
   cfg80211: Calling CRDA to update world regulatory domain
   BUG task_struct (Not tainted): Poison overwritten
   Stack:
    kfree+0x73c/0xad0
    cnmMemFree+0x138/0x268 [wlan_mt76x8_usb]
    rlmDomainSendDomainInfoCmd_V2+0x108/0x1f8 [wlan_mt76x8_usb]
    rlmDomainSendDomainInfoCmd+0x144/0x1dc [wlan_mt76x8_usb]
    rlmDomainSendCmd+0x30/0x48 [wlan_mt76x8_usb]
    mtk_reg_notify+0xe0/0x4bc [wlan_mt76x8_usb]
    wiphy_update_regulatory+0x3f4/0x4c0 [cfg80211]
    set_regdom+0x45c/0x714 [cfg80211]
    reg_regdb_search+0x118/0x14c [cfg80211]

Fix get_sta_stat panic after USB disconnected
1. After USB disconnected, WiFi driver has called wlanRemove() to
   release resources. But upper layer calls riv_driver_get_sta_stat
   after that and causes kernel panic.
2. Add a g_u4HaltFlag checker to in driver command handler.
3. Problem log:
   mtk_usb_disconnect:(HAL STATE) mtk_usb_disconnect()
   Unable to handle kernel NULL pointer dereference at virtual
   address 00000058
   PC is at priv_driver_get_sta_stat+0x2f0/0x157c [wlan_mt76x8_usb]
   LR is at priv_driver_get_sta_stat+0xec/0x157c [wlan_mt76x8_usb]
   [<ffffffbffc3569c0>] priv_driver_get_sta_stat+0x2f0/0x157c
                        [wlan_mt76x8_usb]
   [<ffffffbffc2dcf04>] priv_driver_cmds+0x9bc/0x2830
                        [wlan_mt76x8_usb]
   [<ffffffbffc2dee44>] priv_set_driver+0xcc/0x4c8
                        [wlan_mt76x8_usb]
   [<ffffffc000793400>] ioctl_private_iw_point.isra.2+0xf8/0x1cc

Change-Id: Ic9f8146d58cf30de818815594381eba1fcf58f7a
CR-Id: WCNCR00158507
Feature: misc
Signed-off-by: Alice Ou <alice.ou@mediatek.com>
(cherry picked from commit c8f3a4b93d94c19519d3e1732d4588fdbf5cf5f8)