pbunzip2 1.1.8 uncompressing data compressed with bzip2 on 2-CPU system deadlocks on FreeBSD 10.1

[Jan Mikkelsen]

Machine: Dell Optiplex 755 with an Intel Core-2 Duo running FreeBSD 10.1. pbunzip2 compiled with Clang 3.4 from FreeBSD ports.

Decompressing a file generated by bzip2 from a DVD hangs quickly, all threads showing waiting on "uwait". pbunzip2 consumes no CPU and no forward progress is made.

Running with "-p1" runs to completion.

Recompiling with DPBZIP_DEBUG runs to completion.

Running the code on different hardware with fast I/O runs to completion (eg. Xeon-based server reading from SSDs).

Examining the source code, the DPBZIP_DEBUG case as the following code in consumer_decompress():

                        #ifdef PBZIP_DEBUG
                        safe_cond_timed_wait(fifo->notEmpty, fifo->mut, 1, "consumer");
                        #else
                        safe_cond_wait(fifo->notEmpty, fifo->mut);
                        #endif

Modifying this code to not special-case the debug code reproduces the problem with log output. See attached file for log information.

[Yavor Nikolov (yavor-nikolov)]

Thanks for reporting that. Could you check if the issue reproducible with pbzip2 1.1.10? (Or maybe even with the code on https://code.launchpad.net/~pbzip2/pbzip2/bug-1399589-crash-on-compress-on-os-x)

[Jan Mikkelsen (janm-ubuntu)]

Sorry about the delay -- ran into Christmas the the summer holidays in Australia.

Just tested against 1.1.12, same problem.