New: ipheth stopped working between 2.6.35.9 and 2.6.36.2

Bugme-new Andrew Morton 1 participant 1 message Feb 7, 2011 1 message not in the archive

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Andrew Morton

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2011-02-07 23:07 UTC #1 lore raw

(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).

Quoted 74 lines · On Mon, 7 Feb 2011 19:24:29 GMT [email protected] wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=28552
           Summary: ipheth stopped working between 2.6.35.9 and 2.6.36.2
           Product: Drivers
           Version: 2.5
    Kernel Version: 2.6.36.2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Network
        AssignedTo: [email protected]
        ReportedBy: [email protected]
        Regression: Yes
Created an attachment (id=46762)
--> (https://bugzilla.kernel.org/attachment.cgi?id=46762)
tcpdump of iPhone tethering attempt in 2.6.36.2
Overview:
Internet connection via iPhone 3G ("USB tethering") no longer works in
2.6.36.2; it appears that the packets coming from the iPhone are misinterpreted.
Steps to Reproduce:
1) Connect iPhone to computer via USB cable
2) Put iPhone in "tethering" mode
Actual Results:
The DHCP client times out trying to obtain a lease.
Expected Results:
The computer gets IP information via DHCP, and is able to share the
iPhone's internet connection.
Build Date & Platform:
2.6.36.2 on x86_64
iPhone 3G Firmware 3.1.3
Additional Builds and Platforms:
    2.6.35.9 on x86_64 (same hardware) works as expected.
Additional Information:
Attached are 2 tcpdump logs:
2.6.36.2-tcpdump.txt in the failure case 2.6.35.9-tcpdump.txt, working connection setup
Comparing the DHCP reply at 19:53:36.581403 (works) to 19:05:05.744666 (fails) it appears that 2.6.36.2 misinterprets the data coming from the iPhone, so that the failing packet is not recognized as an IP packet / valid DHCP reply.
The change to ipheth.c itself between 2.6.36 and 2.6.35 seems trivial:
http://lxr.free-electrons.com/diff/drivers/net/usb/ipheth.c?v=2.6.35;diffval=2.6.36;diffvar=v
Therefore I'd at first tried copying 2.6.35's ipheth.c into my 2.6.36 tree and rebuilding this driver; it appears to fail the same as vanilla 2.6.36 does [sorry, no logs - I can repeat this if required].
This suggests that the failure happens somewhere in either the networking or USB layer, not the ipheth.c driver itself.
I'm happy to perform any additional testing required.