tcpdump mailing list archives
Data link level type code
From: "Toeung, Chanthy" <chanthy.toeung () ca kontron com>
Date: Fri, 10 Aug 2007 15:28:11 -0400
Hi all, I need a specific DLT_ value for IPMB protocol. Does anyone know who should i write the email too? I used to write to tcpdump-workers () tcpdump org, but it seems like this email doesn't exist anymore. Thank for your help -----Original Message----- From: tcpdump-workers-owner () lists tcpdump org [mailto:tcpdump-workers-owner () lists tcpdump org]On Behalf Of Saikiran Madugula Sent: Friday, August 10, 2007 3:10 PM To: tcpdump-workers () lists tcpdump org Subject: Re: [tcpdump-workers] libpcap: Memory-loeaks SIGSEGV Hello TJ, The link to libpcap-valgrind.tar.bz2 does not seem to work, can you please check it ? Thanks, Saikiran. TJ wrote:
I've been working on analysing an issue with a cluster of Proliant servers running Debian 2.6.18 64-bit with 4GB RAM on Xeon 3000 CPUs in a data-centre. As part of the diagnosis I have written a tool to check incoming packets. I've used the latest libpcap (0.9.7) built from source. The tool is being developed on a 32-bit system where it runs ok. On the 64-bit servers a SIGSEGV is caused inside libpcap. We've found it happens with the 'standard' Debian 0.9.5 build of libpcap too. In trying to find the cause of the SIGSEGV we've done a lot of testing, including creating a simple test app that uses the same calls to libpcap functions as in the code that SIGSEGVs. Strangely we can't get the libcap test app to SIGSEGV although the code is a copy-paste from the diagnostic app. There seems to be an issue when calls are made to pcap_* functions that pass local (stack) pointers, but as it doesn't always cause SIGSEGV so we're not convinced that is pertinent. The gdb SIGSEGV analysis is further down this email. We ran the libpcap test app through valgrind. In summary, valgrind is reporting: 64-bit libpcap 0.9.5: LEAK SUMMARY: ==9388== definitely lost: 40 bytes in 1 blocks. ==9388== indirectly lost: 939 bytes in 36 blocks. ==9388== possibly lost: 0 bytes in 0 blocks. ==9388== still reachable: 8 bytes in 1 blocks. ==9388== suppressed: 0 bytes in 0 blocks. 32-bit libpcap 0.9.7: ==7910== LEAK SUMMARY: ==7910== definitely lost: 20 bytes in 1 blocks. ==7910== indirectly lost: 555 bytes in 29 blocks. ==7910== possibly lost: 0 bytes in 0 blocks. ==7910== still reachable: 4 bytes in 1 blocks. ==7910== suppressed: 0 bytes in 0 blocks. I'm not sure if these leaks and losses are related to the SIGSEGV but they certainly ought to be cleared up. I've created an archive with the test-libpcap source-code and results of the valgrind test runs with expanded analysis of the leaks and linked to it below (to save on distributing attachments). http://intuitivenipple.net/paketeer/libpcap-valgrind.tar.bz2 TJ. ----- 64 bit gdb of SIGSEGV --------- gdb) run Starting program: /root/packeteer/packeteer -i eth0 -p dst\ host\ 10.33.4.102\ and\ tcp\ port\ 80 [Thread debugging using libthread_db enabled] [New Thread 47255043014096 (LWP 28755)] Packeteer © 2007 TJ http://intuitivenipple.net Licensed on the terms of GPL version 3 Monitoring interface: eth0 pcap filter: dst host 10.33.4.102 and tcp port 80 device eth0 pcap: initialising eth0 with rule "dst host 10.33.4.102 and tcp port 80" pcap_lookupnet() done pcap_openlive() done pcap_freealldevs() done pcap_compile(527690, 7fff3ee3a540, "dst host 10.33.4.102 and tcp port 80", 0, 0) Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 47255043014096 (LWP 28755)] 0x00002afa6bc786b6 in _dl_rtld_di_serinfo () from /lib64/ld-linux-x86-64.so.2 (gdb) bt #0 0x00002afa6bc786b6 in _dl_rtld_di_serinfo () from /lib64/ld-linux-x86-64.so.2 #1 0x00002afa6bc783a2 in _dl_rtld_di_serinfo () from /lib64/ld-linux-x86-64.so.2 #2 0x0000000000405ed3 in pcap_compile () #3 0x0000000000402884 in pcap_init () #4 0x00000000004022dc in main () - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
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Current thread:
- libpcap: Memory-loeaks SIGSEGV TJ (Aug 10)
- Re: libpcap: Memory-loeaks SIGSEGV Saikiran Madugula (Aug 10)
- Data link level type code Toeung, Chanthy (Aug 10)
- Re: Data link level type code Guy Harris (Aug 10)
- Data link level type code Toeung, Chanthy (Aug 10)
- Re: libpcap: Memory-loeaks SIGSEGV Guy Harris (Aug 10)
- Re: libpcap: Memory-loeaks SIGSEGV TJ (Aug 18)
- Re: libpcap: Memory-loeaks SIGSEGV TJ (Aug 18)
- Re: libpcap: Memory-loeaks SIGSEGV TJ (Aug 18)
- Re: libpcap: Memory-loeaks SIGSEGV Saikiran Madugula (Aug 10)