I have a reproducible system hang that appears to be the result of heavy IO.
I originally posted the problem to the linux-block mailing list back in January, but haven't heard back. Not sure if I reported to the correct area. There is a bugzill.kernel.org issue open that contains the details of the problem https://bugzilla.kernel.org/show_bug.cgi?id=193331 The problem occurs if there is a heavy IO load (the system in question is a FTP server that locked up during a heavy load). I am able to reproduce the problem using a btrfs scrub to the file system (the filesystem spans multiple devices). I have a "test system" where I can reproduce the problem at will (it takes only a few minutes to cause the IO to hang up). With a 4.0.5 kernel, I'm unable to reproduce the hang (and the system in question runs just fine). A kernel above 4.4.21 (maybe earlier?) results in the hang described in the above bugzilla ticket. I would appreciate any suggestions on performing further further diagnostics, or if there is additional information needed to dig deeper into the problem. I'm not subscribed to the lkml, so a cc to cheyenne.wi...@gmail.com would be appreciated. Thanks in advance. Cheyenne Wills cheyenne.wi...@gmail.com
