Created attachment 276729 [details] stacktrace See the attached stack trace for the crash. We've experienced the same crash since the early 4.9 series of kernel. It's seems to be quite rare. I've been unable to tie it to any specific workload. It seems to possibly be related to https://lkml.org/lkml/2017/10/31/455 Let me know if you need any further information. I have the full vmcore available.
Unfortunately, no one is likely to pay attention to this bug given how you filed it. The problems are: * You filed this against the ext4 component, and this stack trace doesn't show anything related to ext4 at all; it appears to be a writeback issue. * This is against a 4.9.x (and you mentioned 4.4.x) kernel. The upstream developers generally don't field bug reports against old stable kernels. Customers who need that kind of support pay distributions (e.g,. Red Hat, SuSE, Canonical) to work on those bugs, and the distro kernel engineers will push fixe upstream if they are still applicable. (Or maybe they will find an upstream fix and backport it into their distro kernel.) * You don't have a repro, so we can't even check and see if it is reproducible on the mainline developmment kernel.