Re: [lwip-users] LWIP crash

[Anil kumar]

We are using lwip as a linux kernel module in a multi threaded environment. 

Here is the sequence of events that are leading to the crash in my case.

As the application is continuously sending data, do_write continuously calls do_writemore, which internally calls tcp_write. At some point tcp_write returns ERR_MEM and do_write waits on semaphore op_completed.

When an ack is received from the other end, tcp_input function calls sent_tcp which calls do_writemore, if the state of the connection is NETCONN_WRITE. In do_writemore function access to the data pointer (dataptr) resulting this crash. 

My fix: In sent_tcp function, i am signalling the op_completed semaphore and from do_write function i am calling do_writemore again, which is working fine. 

 What could be the reason for the crash in the first case,  is it i am using lwip threads incorrectly ?

 Please let me know if you need any further clarification.

Thanks,
Anil

On Mon, Sep 3, 2012 at 4:32 PM, Anil kumar <address@hidden> wrote:

Some debugging using prints is indicating that this crash is resulting when the available send buffer size reaches zero. The send buffer size in my opt.h is 32KB and the packet sizes generated by the application is 128. 

The available send buffer reaching zero indicates any leaks ?

Thanks,
Anil

On Fri, Aug 31, 2012 at 5:13 PM, Anil kumar <address@hidden> wrote:

Hi All,

We are using LWIP on linux platform. When we are testing it is crashing repeatedly with the following crash dump.
Any help in this regard would be very much helpful.


Aug 31 15:52:13 neelima-desktop kernel: [  612.495042] *pde = 1bd04067 *pte = 00000000
Aug 31 15:52:13 neelima-desktop kernel: [  612.495110] Modules linked in: lwip(O) ops(O) complib(O) rfcomm bnep bluetooth binfmt_misc i915 drm_kms_helper dr
m ppdev snd_hda_codec_realtek parport_pc snd_hda_intel snd_hda_codec snd_hwdep i2c_algo_bit video snd_pcm snd_seq_midi snd_rawmidi psmouse serio_raw snd_seq
_midi_event snd_seq snd_timer snd_seq_device snd soundcore snd_page_alloc lp parport 8139too 8139cp r8169
Aug 31 15:52:13 neelima-desktop kernel: [  612.495424]
Aug 31 15:52:13 neelima-desktop kernel: [  612.495439] Pid: 2913, comm: tcpip_input_tim Tainted: G           O 3.2.2 #3                  /DG41RQ
Aug 31 15:52:13 neelima-desktop kernel: [  612.495504] EIP: 0060:[<c12a1f2d>] EFLAGS: 00010212 CPU: 1
Aug 31 15:52:13 neelima-desktop kernel: [  612.495541] EIP is at memcpy+0x1d/0x40
Aug 31 15:52:13 neelima-desktop kernel: [  612.495568] EAX: f947c78a EBX: 00000064 ECX: 00000019 EDX: 0811f550
Aug 31 15:52:13 neelima-desktop kernel: [  612.495607] ESI: 0811f550 EDI: f947c78a EBP: dbffde18 ESP: dbffde0c
Aug 31 15:52:13 neelima-desktop kernel: [  612.495644]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Aug 31 15:52:13 neelima-desktop kernel: [  612.495739]  00000064 f947c78a 0811f550 dbffde3c f92ea0fe f92f6db4 f947c78a 0811f550
Aug 31 15:52:13 neelima-desktop kernel: [  612.495809]  00000064 f947c2d0 00000064 f92fb930 dbffdeb8 f92f21de f92f9303 f947c78a
Aug 31 15:52:13 neelima-desktop kernel: [  612.495879]  0811f550 00000000 00000056 c1901496 0000de66 00000064 205b0246 32313620
Aug 31 15:52:13 neelima-desktop kernel: [  612.495983]  [<f92ea0fe>] lwip_chksum_copy+0x3e/0x60 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92f21de>] tcp_write+0x66e/0x990 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e6f74>] do_writemore+0x164/0x370 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e73c0>] ? poll_tcp+0xb0/0xb0 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e743f>] sent_tcp+0x7f/0xc0 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92eef67>] ? tcp_parseopt.isra.0+0x27/0xe0 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e73c0>] ? poll_tcp+0xb0/0xb0 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92ef5d5>] tcp_input+0x5b5/0xf30 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92eb562>] ip_input+0x2b2/0x2d0 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e959b>] ethernet_input+0x7b/0x330 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c1026288>] ? default_spin_lock_flags+0x8/0x10
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c156fdbd>] ? _raw_spin_lock_irqsave+0x2d/0x40
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c106ba19>] ? down+0x29/0x40
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e8220>] ? pbuf_free_int+0x10/0x10 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e831c>] tcpip_thread+0xfc/0x160 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<f92e8220>] ? pbuf_free_int+0x10/0x10 [lwip]
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c1065dcd>] kthread+0x6d/0x80
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c1065d60>] ? flush_kthread_worker+0x80/0x80
Aug 31 15:52:13 neelima-desktop kernel: [  612.496003]  [<c1576efe>] kernel_thread_helper+0x6/0x10
Aug 31 15:52:14 neelima-desktop kernel: [  612.557620] ---[ end trace 333a796a57491d86 ]---

Thanks,
Anil