Re: [PATCH v8 1/4] ath10k: disable TX complete indication of htt for sdio

[Wen Gong <wgong@codeaurora.org>]

On 2020-02-11 19:11, Pi-Hsun Shih wrote:
> On Tue, Feb 11, 2020 at 5:46 PM Wen Gong <wgong@codeaurora.org> wrote:
>> 
>> On 2020-02-11 15:03, Pi-Hsun Shih wrote:
>> > Hi,
>> >
>> > On 11/28/19 6:30 PM, Wen Gong wrote:
>> >> ...
>> >> diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c
>> >> b/drivers/net/wireless/ath/ath10k/htt_tx.c
>> >> index a182c0944cc7..c6c4b2a4d20f 100644
>> >> --- a/drivers/net/wireless/ath/ath10k/htt_tx.c
>> >> +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c
>> >> @@ -543,7 +543,35 @@ void ath10k_htt_tx_free(struct ath10k_htt *htt)
>> >>     void ath10k_htt_htc_tx_complete(struct ath10k *ar, struct sk_buff
>> >> *skb)
>> >>   {
>> >> +    struct ath10k_htt *htt = &ar->htt;
>> >> +    struct htt_tx_done tx_done = {0};
>> >> +    struct htt_cmd_hdr *htt_hdr;
>> >> +    struct htt_data_tx_desc *desc_hdr;
>> >> +    u16 flags1;
>> >> +
>> >>      dev_kfree_skb_any(skb);
>> >> +
>> >> +    if (!htt->disable_tx_comp)
>> >> +            return;
>> >> +
>> >> +    htt_hdr = (struct htt_cmd_hdr *)skb->data;
>> >
>> > skb is already freed on the above line (dev_kfree_skb_any) but is
>> > still used here, should the dev_kfree_skb_any be moved to the end of
>> > this function?
>> >
>> skb will not freed on the above line, please see this patch
>> https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git/commit/drivers/net/wireless/ath/ath10k?h=ath-next&id=30382dd1cf3a141bfaa568ee183c1892090fa79a
> 
> IIUC the commit only makes the skb not freed in ieee80211_tx_status,
> but it's still freed in ath10k_htt_htc_tx_complete (by
> dev_kfree_skb_any)?
> 
> While booting with this patch (and the
> 30382dd1cf3a141bfaa568ee183c1892090fa79a commit) with kernel bootargs
> "slub_debug=FZPUA", I got a kernel panic in ath10k module:
> 
> [   16.058676] Unable to handle kernel paging request at virtual
> address 006b6b6b6b6b6b6b
> [   16.066613] Mem abort info:
> [   16.069419]   ESR = 0x96000004
> [   16.072481]   Exception class = DABT (current EL), IL = 32 bits
> [   16.078406]   SET = 0, FnV = 0
> [   16.081476]   EA = 0, S1PTW = 0
> [   16.084624] Data abort info:
> [   16.087513]   ISV = 0, ISS = 0x00000004
> [   16.091369]   CM = 0, WnR = 0
> [   16.094354] [006b6b6b6b6b6b6b] address between user and kernel 
> address ranges
> [   16.101503] Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [   16.107071] Modules linked in: ath10k_sdio ath10k_core ath mac80211
> cfg80211 lzo_rle lzo_compress zram asix usbnet mii joydev
> [   16.118380] Process kworker/u16:2 (pid: 142, stack limit =
> 0x00000000082e3c57)
> [   16.125597] CPU: 7 PID: 142 Comm: kworker/u16:2 Not tainted 4.19.102 
> #48
> [   16.132287] Hardware name: MediaTek krane sku176 board (DT)
> [   16.137862] Workqueue: ath10k_sdio_wq ath10k_sdio_write_async_work
> [ath10k_sdio]
> [   16.145251] pstate: 60000005 (nZCv daif -PAN -UAO)
> [   16.150051] pc : ath10k_htt_htc_tx_complete+0xe0/0x1a4 [ath10k_core]
> [   16.156411] lr : ath10k_htt_htc_tx_complete+0xdc/0x1a4 [ath10k_core]
> [   16.162755] sp : ffffff800888bc80
> [   16.166061] x29: ffffff800888bc90 x28: ffffffd892b08c20
> [   16.171363] x27: ffffffd892b173f8 x26: ffffffd892b08c20
> [   16.176666] x25: ffffffd897337240 x24: ffffffd892b16b48
> [   16.181968] x23: 6b6b6b6b6b6b6b6b x22: ffffff970d2a1000
> [   16.187270] x21: ffffff970d2a0000 x20: ffffffd897337240
> [   16.192572] x19: ffffffd892b01960 x18: 0000000000000000
> [   16.197873] x17: 000000000000003c x16: ffffff970edefba0
> [   16.203174] x15: 0000000000000006 x14: ffff001000000600
> [   16.208475] x13: 00000000000064e6 x12: 0000000000000000
> [   16.213777] x11: 0000000000000000 x10: 0000000000000000
> [   16.219079] x9 : b307f4e257a4e000 x8 : b307f4e257a4e000
> [   16.224391] x7 : 0000000000000000 x6 : ffffff970f970e9c
> [   16.229712] x5 : 0000000000000027 x4 : 0000000000000000
> [   16.235030] x3 : 000000000002ed25 x2 : ffffffd8bff94fd8
> [   16.240341] x1 : ffffffd8bff8c0c8 x0 : 0000000000000034
> [   16.245644] Call trace:
> [   16.248109]  ath10k_htt_htc_tx_complete+0xe0/0x1a4 [ath10k_core]
> [   16.254123]  ath10k_htc_notify_tx_completion+0xe4/0x118 
> [ath10k_core]
> [   16.260559]  ath10k_sdio_write_async_work+0x158/0x1f4 [ath10k_sdio]
> [   16.266823]  process_one_work+0x208/0x408
> [   16.270825]  worker_thread+0x23c/0x3e4
> [   16.274566]  kthread+0x120/0x130
> [   16.277788]  ret_from_fork+0x10/0x18
> [   16.281357] Code: 528046a3 aa1303e0 97ffc028 f9406a97 (394002e8)
> [   16.287442] ---[ end trace 3bae4173512bf484 ]---
> [   16.298803] Kernel panic - not syncing: Fatal exception
> [   16.304033] SMP: stopping secondary CPUs
> [   16.308072] Kernel Offset: 0x1706400000 from 0xffffff8008000000
> [   16.313983] CPU features: 0x0,2188200c
> [   16.317721] Memory Limit: none
> 
> So it seems that the skb is used-after-free in 
> ath10k_htt_htc_tx_complete here.
I guess the panic is because of a tx mgmt frame.
did you connect to an AP?
is the panic easy to happen?

Could you apply this change and collect message if panic(
also apply 30382dd1cf3a141bfaa568ee183c1892090fa79a and ath10k: disable 
TX complete indication of htt for sdio)?
it will print some useful info with ath10k_warn.

diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c 
b/drivers/net/wireless/ath/ath10k/htt_tx.c
index 51f060a00b95..b1f768271331 100644
--- a/drivers/net/wireless/ath/ath10k/htt_tx.c
+++ b/drivers/net/wireless/ath/ath10k/htt_tx.c
@@ -555,6 +555,21 @@ void ath10k_htt_htc_tx_complete(struct ath10k *ar, 
struct sk_buff *skb)
         struct htt_data_tx_desc *desc_hdr;
         u16 flags1;

+       htt_hdr = (struct htt_cmd_hdr *)skb->data;
+
+       ath10k_warn(ar, "msg_type: %d\n", htt_hdr->msg_type);
+
+       if (htt_hdr->msg_type == HTT_H2T_MSG_TYPE_TX_FRM) {
+               desc_hdr = (struct htt_data_tx_desc *)
+                       (skb->data + sizeof(*htt_hdr));
+               flags1 = __le16_to_cpu(desc_hdr->flags1);
+
+               if (flags1 & HTT_DATA_TX_DESC_FLAGS1_TX_COMPLETE)
+                       ath10k_warn(ar, "htt tx mgmt\n");
+               else
+                       ath10k_warn(ar, "htt tx data\n");
+       }
+
         dev_kfree_skb_any(skb);

         if (!htt->disable_tx_comp)