buglwIP - A Lightweight TCP/IP stack - Bugs: bug #39124, fragmented ICMP output corrupted...

 
 

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bug #39124: fragmented ICMP output corrupted by IGMP input

Submitter:  beaujouan <rico37>
Submitted:  Thu 30 May 2013 01:52:08 PM UTC
   
 
Category:  IPv4 Severity:  3 - Normal
Item Group:  Faulty Behaviour Status:  Fixed
Privacy:  Public Assigned to:  goldsimon
Open/Closed:  Closed Planned Release:  None
lwIP version:  1.3.1

Jump to the original submission

Thu 26 Feb 2015 09:34:15 PM UTC, comment #6: 

Without getting more input, this looks too much like a threading issue in the port to leave it open as a bug in core lwIP code.

Simon Goldschmidt <goldsimon>
Group administrator
Mon 01 Jul 2013 01:05:28 PM UTC, comment #5: 

based on what you said, conditions for having a thread safe pbuf alloc/free are met, so yes, it is ! :)

Sylvain Rochet <gradator>
Group Member
Mon 01 Jul 2013 12:59:34 PM UTC, comment #4: 

Thanks for your comment Sylvain,

SYS_LIGHTWEIGHT_PROT is set to 1 and sys_arch_protect/sys_arch_unprotect are defined disabling/enabling the MCU global interrupts.

In fact we are using the sys_arch port from Texas Instrument for LM3S9D96 MCU.

So regarding your comments, the pbuf is really thread safe, isn't it ?

beaujouan <rico37>
Mon 01 Jul 2013 12:44:09 PM UTC, comment #3: 

pbuf alloc/free operations are thread safe if SYS_LIGHTWEIGHT_PROT is set and sys_arch_protect() / sys_arch_unprotect() defined.

Sylvain Rochet <gradator>
Group Member
Mon 01 Jul 2013 11:55:56 AM UTC, comment #2: 

We are using lwIP in a multithreaded environnment (SafeRTOS) so NO_SYS is defined to 0.

I thought pbuf management was thread safe.
How can I be sure that it is due to a multi thread issue ?

beaujouan <rico37>
Fri 28 Jun 2013 08:04:42 PM UTC, comment #1: 

Are you absolutely sure this isn't a threading problem? I do not undertand why and incoming packet should corrupt an outgoing packet when lwIP is not multithreaded.

Simon Goldschmidt <goldsimon>
Group administrator
Thu 30 May 2013 01:52:08 PM UTC, original submission:  

Hello,

I am new to savannah, hoping I post in the right place.

First, bug reports to lwIP 1.3.2 but it was not listed in lwIP version list, so I selected 1.3.1.

The bug is, when lwIP send a fragmented ICMP Echo reply, this output frame can be corrupted by an IGMP incoming request.

I have seen the bug #35616 report which seems to be very similar but does not concern lwIP 1.3.2.

According to this bug, in my configuration, ETH_PAD_SIZE = 2 and MEM_ALIGNMENT=4, so I am not sure that issue is the same as in the bug #35616

I think there may be a freeing issue, allowing pbuf used in output frame to be used when receiving the IGMP incoming frame but I am a little bit lost in the pbuf mecanism.

Is there a known fix I did not catch ?
Is there some other information that can I provide to help understanding ?

Regards,

beaujouan <rico37>

 

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2015-02-26 goldsimon StatusNeed Info Fixed
        Assigned toNone goldsimon
        Open/ClosedOpen Closed
    2013-06-28 goldsimon StatusNone Need Info

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