[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Indeterminism in tarlz's test suite

From: Antonio Diaz Diaz
Subject: Re: Indeterminism in tarlz's test suite
Date: Mon, 19 Apr 2021 19:18:33 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i586; en-US; rv: Gecko/20110420 SeaMonkey/2.0.14

Hi Florian,

Florian Schmaus wrote:
testing bad input...tarlz: Exiting with failure status due to previous

Thank you very much for reporting this.

The problem is in fact a race happening on a test archive with a format violation put there on purpose, and only can happen when more than 2 threads are being used.

The archive in question contains a directory with a long name requiring an extended header, and a global header has been inserted in its own lzip member between the extended header and the ustar header like this:

| extended header | global header | ustar header |

The problem happens when the thread decoding the ustar header finishes before the thread decoding the extended header has time to realize that its lzip member is incomplete.

I have fixed the problem by making the thread decoding the ustar header signal the error in a way that can later be overridden by another thread.

The underlying problem is that the pax format is not really adequate for parallel decoding, forcing tarlz to jump through a lot of hoops to achieve it. I hope a new tar format can be designed with parallel decoding in mind.

I'll release a fixed version as soon as I test the fix and finish a couple more things.

Best regards,

reply via email to

[Prev in Thread] Current Thread [Next in Thread]