When device is running and the interface status is changed, the gpf issue
is triggered. The problem triggering process is as follows:
Thread A: Thread B
ieee80211_runtime_change_iftype() process_one_work()
... ...
ieee80211_do_stop() ...
... ...
sdata->bss = NULL ...
... ieee80211_subif_start_xmit()
ieee80211_multicast_to_unicast
//!sdata->bss->multicast_to_unicast
cause gpf issue
When the interface status is changed, the sending queue continues to send
packets. After the bss is set to NULL, the bss is accessed. As a result,
this causes a general-protection-fault issue.
The following is the stack information:
general protection fault, probably for non-canonical address
0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f]
Workqueue: mld mld_ifc_work
RIP: 0010:ieee80211_subif_start_xmit+0x25b/0x1310
Call Trace:
<TASK>
dev_hard_start_xmit+0x1be/0x990
__dev_queue_xmit+0x2c9a/0x3b60
ip6_finish_output2+0xf92/0x1520
ip6_finish_output+0x6af/0x11e0
ip6_output+0x1ed/0x540
mld_sendpack+0xa09/0xe70
mld_ifc_work+0x71c/0xdb0
process_one_work+0x9bf/0x1710
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30
</TASK>
Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
Reported-by: [email protected]
Signed-off-by: Zhengchao Shao <[email protected]>
---
net/mac80211/tx.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a364148149f9..c38485f39d2b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -4418,6 +4418,11 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
if (likely(!is_multicast_ether_addr(eth->h_dest)))
goto normal;
+ if (unlikely(!ieee80211_sdata_running(sdata))) {
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+
if (unlikely(ieee80211_multicast_to_unicast(skb, dev))) {
struct sk_buff_head queue;
--
2.17.1
> -----Original Message-----
> From: Zhengchao Shao <[email protected]>
> Sent: Wednesday, October 26, 2022 10:47 AM
> To: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; [email protected]
> Cc: [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: [PATCH net,v2] wifi: mac80211: fix general-protection-fault in ieee80211_subif_start_xmit()
>
> When device is running and the interface status is changed, the gpf issue
> is triggered. The problem triggering process is as follows:
> Thread A: Thread B
> ieee80211_runtime_change_iftype() process_one_work()
> ... ...
> ieee80211_do_stop() ...
> ... ...
> sdata->bss = NULL ...
> ... ieee80211_subif_start_xmit()
> ieee80211_multicast_to_unicast
> //!sdata->bss->multicast_to_unicast
> cause gpf issue
>
> When the interface status is changed, the sending queue continues to send
> packets. After the bss is set to NULL, the bss is accessed. As a result,
> this causes a general-protection-fault issue.
>
> The following is the stack information:
> general protection fault, probably for non-canonical address
> 0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f]
> Workqueue: mld mld_ifc_work
> RIP: 0010:ieee80211_subif_start_xmit+0x25b/0x1310
> Call Trace:
> <TASK>
> dev_hard_start_xmit+0x1be/0x990
> __dev_queue_xmit+0x2c9a/0x3b60
> ip6_finish_output2+0xf92/0x1520
> ip6_finish_output+0x6af/0x11e0
> ip6_output+0x1ed/0x540
> mld_sendpack+0xa09/0xe70
> mld_ifc_work+0x71c/0xdb0
> process_one_work+0x9bf/0x1710
> worker_thread+0x665/0x1080
> kthread+0x2e4/0x3a0
> ret_from_fork+0x1f/0x30
> </TASK>
>
> Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
> Reported-by: [email protected]
> Signed-off-by: Zhengchao Shao <[email protected]>
> ---
> net/mac80211/tx.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index a364148149f9..c38485f39d2b 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -4418,6 +4418,11 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
> if (likely(!is_multicast_ether_addr(eth->h_dest)))
> goto normal;
>
> + if (unlikely(!ieee80211_sdata_running(sdata))) {
> + kfree_skb(skb);
> + return NETDEV_TX_OK;
> + }
> +
The indent looks odd. It seems like you use spaces instead of tabs?
> if (unlikely(ieee80211_multicast_to_unicast(skb, dev))) {
> struct sk_buff_head queue;
>
> --
> 2.17.1
>
>
> ------Please consider the environment before printing this e-mail.
On 2022/10/26 13:46, Ping-Ke Shih wrote:
>
>
>> -----Original Message-----
>> From: Zhengchao Shao <[email protected]>
>> Sent: Wednesday, October 26, 2022 10:47 AM
>> To: [email protected]; [email protected]; [email protected];
>> [email protected]; [email protected]; [email protected]; [email protected]
>> Cc: [email protected]; [email protected]; [email protected]; [email protected];
>> [email protected]; [email protected]
>> Subject: [PATCH net,v2] wifi: mac80211: fix general-protection-fault in ieee80211_subif_start_xmit()
>>
>> When device is running and the interface status is changed, the gpf issue
>> is triggered. The problem triggering process is as follows:
>> Thread A: Thread B
>> ieee80211_runtime_change_iftype() process_one_work()
>> ... ...
>> ieee80211_do_stop() ...
>> ... ...
>> sdata->bss = NULL ...
>> ... ieee80211_subif_start_xmit()
>> ieee80211_multicast_to_unicast
>> //!sdata->bss->multicast_to_unicast
>> cause gpf issue
>>
>> When the interface status is changed, the sending queue continues to send
>> packets. After the bss is set to NULL, the bss is accessed. As a result,
>> this causes a general-protection-fault issue.
>>
>> The following is the stack information:
>> general protection fault, probably for non-canonical address
>> 0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN
>> KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f]
>> Workqueue: mld mld_ifc_work
>> RIP: 0010:ieee80211_subif_start_xmit+0x25b/0x1310
>> Call Trace:
>> <TASK>
>> dev_hard_start_xmit+0x1be/0x990
>> __dev_queue_xmit+0x2c9a/0x3b60
>> ip6_finish_output2+0xf92/0x1520
>> ip6_finish_output+0x6af/0x11e0
>> ip6_output+0x1ed/0x540
>> mld_sendpack+0xa09/0xe70
>> mld_ifc_work+0x71c/0xdb0
>> process_one_work+0x9bf/0x1710
>> worker_thread+0x665/0x1080
>> kthread+0x2e4/0x3a0
>> ret_from_fork+0x1f/0x30
>> </TASK>
>>
>> Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
>> Reported-by: [email protected]
>> Signed-off-by: Zhengchao Shao <[email protected]>
>> ---
>> net/mac80211/tx.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
>> index a364148149f9..c38485f39d2b 100644
>> --- a/net/mac80211/tx.c
>> +++ b/net/mac80211/tx.c
>> @@ -4418,6 +4418,11 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
>> if (likely(!is_multicast_ether_addr(eth->h_dest)))
>> goto normal;
>>
>> + if (unlikely(!ieee80211_sdata_running(sdata))) {
>> + kfree_skb(skb);
>> + return NETDEV_TX_OK;
>> + }
>> +
>
> The indent looks odd. It seems like you use spaces instead of tabs?
>
Hi Shih:
Thank you for your review. I will fix it in V3.
Zhengchao Shao
>> if (unlikely(ieee80211_multicast_to_unicast(skb, dev))) {
>> struct sk_buff_head queue;
>>
>> --
>> 2.17.1
>>
>>
>> ------Please consider the environment before printing this e-mail.
>