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qcacld-3.0: Fix DP thread stuck issue due to rtnl lock

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scenario:
(1) thread A is doing hdd_stop_adapter() and the caller outside of
hdd_stop_adapter will acquire the rtnl lock, dp_vdev_detach_wifi3()
in hdd_stop_adpater() will notify DP thread B flush stack GRO frames
and wait DP thread B response/set vdev delete event.
(2) but if DP thread B is under processing RX frames and do local
ARP check for ARP request, it will wait and try to acquire rtnl
lock as well, dead lock happened. Until thread A wait vdev delete
event timeout and corressponding net_dev/hdd_adapter is freed, then
DP thread B get chance to acquire rtnl lock but hdd_adapter/net_dev
has been freed, hit panic.

Use rtnl_trylock() instead of rtnl_lock() in hdd_is_arp_local(),
if rtnl_trylock() failed, assume this is local ARP and return,
else do the local ARP checking same as before.

Change-Id: Ic6724b68f6e09e9d139c430396e4c76bf483d033
CRs-Fixed: 2760979
This commit is contained in:
Jinwei Chen 2020-08-24 21:51:51 -07:00 • committed by snandini
commit b79fd0c6ec
1 changed files with 4 additions and 1 deletions
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5
core/hdd/src/wlan_hdd_tx_rx.c
View file

@ -1540,7 +1540,10 @@ static bool hdd_is_arp_local(struct sk_buff *skb)
arp = (struct arphdr *)skb->data;
if (arp->ar_op == htons(ARPOP_REQUEST)) {
rtnl_lock();
/* if fail to acquire rtnl lock, assume it's local arp */
if (!rtnl_trylock())
return true;
in_dev = __in_dev_get_rtnl(skb->dev);
if (in_dev) {
for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;