Bug 79091

Summary:	Bug in Kernel's LZ4-HC in 64bit (kernel crypto library)
Product:	Other	Reporter:	Kiran Kankipati (kiran.cyberpro)
Component:	Other	Assignee:	Greg Kroah-Hartman (greg)
Status:	NEW ---
Severity:	high	CC:	greg, kiran.cyberpro
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	3.15.2, 3.15.1	Subsystem:
Regression:	No	Bisected commit-id:

Description Kiran Kankipati 2014-06-28 05:54:37 UTC

Hi

I am using kernel's LZ4-HC for lossless compression for optimization of packets in TrafficSqueezer. So far LZ4-HC is working fine with 32bit kernel mode. But in 64bit machine, it is creating trouble. I did lot of debugging and finally pointed the source of the problem lies purely within LZ4-HC kernel crypto library.

I am also facing buffer overrun issues with LZ4-HC 64bit mode.

I reported to the guy who ported LZ4-HC within kernel, so far I didnt got any reply. Is there someone who are facing similar issue ?

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FYI, some packets are getting processed normally with LZ4-HC (64bit with no issues). But randomly some are getting corrupt.

I confirmed and checked replacing the LZ4-HC with LZO libarary in my TrafficSqueezer API calls. Since LZO apis are 99% similar to LZ4-HC. I found LZO works perfect with no issues with large number of packet samples.

Awaiting your help.
Thank you.
__________________
cheers, Kiran Kankipati
Founder: TrafficSqueezer - Linux Kernel open-source WAN optimization
Website: www.trafficsqueezer.org

Comment 1 Greg Kroah-Hartman 2014-06-28 16:01:09 UTC

Let's track this through email.

Comment 2 Kiran Kankipati 2014-06-28 16:14:23 UTC

Thanks a lot Greg for your email !

As you suggested I am happy to wait till 3.17 releses for fixed LZ4-HC. I can't get and use any patches as of now (although it is available). I need it as a part of complete bundle. So I can wait.

Thank you, cheers, Kiran

Comment 3 Kiran Kankipati 2014-11-16 21:39:11 UTC

Important update:

I just recently tried with 3.17.3 via my TrafficSqueezer code in x86 64bit.

Found that LZ4 now works fine. But the LZ4-HC variant still has the inconsistency problem.

cheers, Kiran