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I have troubles trying to dial USB 3G connection using pppd.

Everytime I try to run #pppd call provider, it ends up with Segmentation Fault.

  • modem drivers are installed successfuly, modem is responding to AT commands without issues
  • kernel support for PPP is included
  • chat script for initialization AT commands works properly

I tried pppd versions 2.4.4. and 2.4.5., still same issue.

Platform is ARM (armv4l), with Debian Lenny. Kernel version 2.6.24.4.

Any ideas what else to try?

Here is a related part of dmesg output

[40642.660000] skb_over_panic: text:bf0563ec len:22 put:22 head:c3d98200 data:c3d98200 tail:0xc3d98200 end:0xc3d98240 dev:<NULL>
[40642.660000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[40642.660000] pgd = c0400000
[40642.660000] [00000000] *pgd=03f11031, *pte=00000000, *ppte=00000000
[40642.660000] Internal error: Oops: 817 [#3]
[40642.660000] Modules linked in: ppp_deflate zlib_deflate zlib_inflate ppp_async ppp_generic slhc crc_ccitt dc_acm uhci_hcd g_ether str8100_udc ohci_hcd usb_storage sd_mod scsi_mod ehci_hcd usbcore
[40642.660000] CPU: 0    Tainted: G      D  (2.6.24.4 #1)
[40642.660000] pc : [<c013e13c>]    lr : [<c01f2a74>]    psr: 20000013
[40642.660000] sp : c2659eec  ip : c2659e3c  fp : c2659f1c
[40642.660000] r10: 00000000  r9 : fffffff2  r8 : 00053542
[40642.660000] r7 : c3d98240  r6 : c3d98200  r5 : c3d98200  r4 : c3d98200
[40642.660000] r3 : 00000000  r2 : c020257c  r1 : 00004659  r0 : 00000084
[40642.660000] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[40642.660000] Control: 0000397f  Table: 00400000  DAC: 00000015
[40642.660000] Process pppd (pid: 2111, stack limit = 0xc2658258)
[40642.660000] Stack: (0xc2659eec to 0xc265a000)
[40642.660000] 9ee0: c3d98200 c3d98200 c3d98200 c3d98240 c01d0d20
[40642.660000] 9f00: c34e3700 00000016 c3d3e3e0 c2659f78 c2659f50 c2659f20 bf0563f8 c013e0f8
[40642.660000] 9f20: 00000200 c2d32700 c39a86e0 00053542 00000016 c2659f78 00000000 c2658000
[40642.660000] 9f40: 0000c227 c2659f74 c2659f54 c007aee0 bf056360 00000000 c39a8700 c39a86e0
[40642.660000] 9f60: c2659f78 00000000 c2659fa4 c2659f78 c007b014 c007ae2c 00000000 00000000
[40642.660000] 9f80: 00000000 00000016 00053542 00000008 00000004 c001ff44 00000000 c2659fa8
[40642.660000] 9fa0: c001fda0 c007afd8 00000016 00053542 00000008 00053542 00000016 000080fb
[40642.660000] 9fc0: 00000016 00053542 00000008 00000000 000387e0 0000c021 0000c227 000552a8
[40642.660000] 9fe0: 00000000 befdec8c 000299c8 40120384 60000010 00000008 00000000 00000000
[40642.660000] Backtrace:
[40642.660000] Function entered at [<c013e0e8>] from [<bf0563f8>]
[40642.660000]  r7:c2659f78 r6:c3d3e3e0 r5:00000016 r4:c34e3700
[40642.660000] Function entered at [<bf056350>] from [<c007aee0>]
[40642.660000] Function entered at [<c007ae1c>] from [<c007b014>]
[40642.660000]  r7:00000000 r6:c2659f78 r5:c39a86e0 r4:c39a8700
[40642.660000] Function entered at [<c007afc8>] from [<c001fda0>]
[40642.660000]  r8:c001ff44 r7:00000004 r6:00000008 r5:00053542 r4:00000016
[40642.660000] Code: e88d00f0 e58dc010 ebfbf5c3 e3a03000 (e5833000)
[40642.660000] ---[ end trace a65fdacfd46d8588 ]---
share|improve this question
Debian lenny? Update that antique first. – Michael Hampton Jan 8 at 15:55
If you're able to rebuild the kernel, you could include debug info as described on bugcommunity.com/wiki/index.php/Debug_an_oops to get closer to the reason. – ott-- Jan 8 at 16:51
Yes, Debian Lenny. It's on TS-7500 embedded PC with arm architecture. I will be happy to upgrade when there will be support from side of manufacturer. – vladik Jan 29 at 16:03
After lot of debuging I finally found the problem. It was as usual between chair and keyboard. Modules are present, but platform was not configured to boot actule kernel from appropriate memory device. Since this is done by external trigger it's easy to overlook (at least it was for me). – vladik Jan 29 at 16:10

closed as off topic by SvW, mdpc, Scott Pack, Ward, Khaled Jan 9 at 7:37

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