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Date: Sun, 17 May 2015 22:22:45 +0300
Message-ID: <CAJ=9CzaDK+oKJ8JJtb_OE6wrh85f8ffPf_oa9c0GRQFStUULjg@mail.gmail.com> (sfid-20150517_212249_719855_07368057)
Subject: Re: kernel page fault in r8712u
From: Haggai Eran <haggai.eran@gmail.com>
To: Arend van Spriel <aspriel@gmail.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>,
	Florian Schilhabel <florian.c.schilhabel@googlemail.com>,
	linux-wireless@vger.kernel.org
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I added some debugging prints, trying to see more details about the
packet that fails the r8712_validate_recv_frame. I noticed I'm getting
many packets where recv_decache returns _FAIL. However, the last two
packets before the crash fail for different reasons. The first has the
ver field set to 3 (instead of zero). The second (the one that get's
freed and cause the crash apparently) has an unknown type (12). If I'm
not mistaken, 12 = WIFI_CTRL_TYPE | WIFI_DATA_TYPE. Is that possible?

It could be that the packet headers are garbled though.

Haggai

On 17 May 2015 at 20:20, Haggai Eran <haggai.eran@gmail.com> wrote:
> On 17 May 2015 at 13:29, Arend van Spriel <aspriel@gmail.com> wrote:
>> On 17-05-15 06:25, Haggai Eran wrote:
>>>
>>> On 16 May 2015 at 20:54, Larry Finger <Larry.Finger@lwfinger.net> wrote:
>>>>
>>>> Another location needed from gdb is "l *recv_func+0x8c".
>>>
>>>
>>> Here it is:
>>> (gdb) l *recv_func+0x8c
>>> 0x17094 is in recv_func (drivers/staging/rtl8712/rtl8712_recv.c:1004).
>>> 999                     r8712_free_recvframe(orig_prframe,
>>> pfree_recv_queue);
>>> 1000                    goto _exit_recv_func;
>>> 1001            }
>>> 1002    _exit_recv_func:
>>> 1003            return retval;
>>> 1004    }
>>> 1005
>>> 1006    static int recvbuf2recvframe(struct _adapter *padapter, struct
>>> sk_buff *pskb)
>>> 1007    {
>>> 1008            u8 *pbuf, shift_sz = 0;
>>>
>>> I don't think this means the relevant call is the one at line 999. I
>>> think it is an earlier call, after r8712_validate_recv_frame. Here's
>>> the disassembly:
>>
>>
>> can you provide the address of recv_func as well to determine the exact
>> location in assembly.
>
> Yes, it is in offset 0x17008 in the module:
>> 00017008 <recv_func>:
>
> Regards,
> Haggai
>
>>
>>>          /* check the frame crtl field and decache */
>>>          retval = r8712_validate_recv_frame(padapter, prframe);
>>>     17070:       e1a00004        mov     r0, r4
>>>     17074:       e1a01005        mov     r1, r5
>>>     17078:       ebfffffe        bl      17bc0 <r8712_validate_recv_frame>
>>>          if (retval != _SUCCESS) {
>>>     1707c:       e3500001        cmp     r0, #1
>>>                          r8712_free_recvframe(orig_prframe,
>>> pfree_recv_queue);
>>>                          goto _exit_recv_func;
>>>                  }
>>>          }
>>>          /* check the frame crtl field and decache */
>>>          retval = r8712_validate_recv_frame(padapter, prframe);
>>>     17080:       e1a06000        mov     r6, r0
>>>          if (retval != _SUCCESS) {
>>>     17084:       0a000005        beq     170a0 <recv_func+0x98>
>>>                  /* free this recv_frame */
>>>                  r8712_free_recvframe(orig_prframe, pfree_recv_queue);
>>>     17088:       e1a00005        mov     r0, r5
>>>     1708c:       e1a01007        mov     r1, r7
>>>     17090:       ebfffffe        bl      166e8 <r8712_free_recvframe>
>>>                  r8712_free_recvframe(orig_prframe, pfree_recv_queue);
>>>                  goto _exit_recv_func;
>>>          }
>>> _exit_recv_func:
>>>          return retval;
>>> }
>>>     17094:       e1a00006        mov     r0, r6