"As far as mksquashfs is concerned, it is being invoked in the usual way as an independent subprocess."
What is the exact command line passed to Mksquashfs? (from looking at the Transparent Archivist tool's source code it doesn't seem to be passing any non-standard options). "Sometimes -- not very often, maybe once in 30-60 invocations -- mksquashfs simply hangs." Is this 30-60 invocations of Mksquashfs (by the Transparent Archivist tool) or 30-60 invocations of the Transparent Archivist tool (which is expected to invoke Mksquashfs itself multiple times)? "Having made some of the filesystem it's supposed to be making, It stops making the filesystem for no apparent reason. It continues to use a wee bit of processing power after that -- very occasionally rising to the top of the "top" display -- but it makes no observable progress on the filesystem that it's supposed to be making. Once I left it running for 4 days; no progress, and no resumption of work occurred during all that time." With difficult to track down bugs (as this will be if it is a threading issue), even the smallest amount of clues can be useful. The fact that Mksquashfs when hung occasionally rises to the top of the top display suggests it is doing something (even though it is making no progress). This in turns suggests the hang is a "livelock" issue rather than a "deadlock" issue (in which case Mksquashfs will consume no CPU). When Mksquashfs rises to the top of the top display how much CPU is it using? and how often does it rise to the top of the top display? As you've proved to be comfortable with modifying the Transparent Archivist tool's source code to alter the Mksquashfs invocation parameters, it would to useful to add the following options -no-progress -info This addresses two issues: First it gets rid of the progress bar (with the twirling progress indicator), which as this is handled by a separate thread could be completely responsible for Mksquashfs occasionally appearing in the top of top - this is unlikely unless your system is doing absolutely nothing else, but -no-progress eliminates that potential red herring. Second it makes Mksquashfs display files as they are processed, in particular it will show the files processed immediately before Mksquashfs hangs. If over a number of hangs, the files processed before the hang are identical it will strongly suggest there is something about these files which are causing Mksquashfs to hang. This information will be extremely useful. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/722168 Title: mksquashfs hangs -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
