On 12/28/17 12:19, Paolo Valente wrote: (snip half a tech report ;) So either this or the previous patch ("limit tags for writes and async I/O" can lead to a hard, unrecoverable hang with heavy writes. Since I couldn't log into the affected system anymore I couldn't get any stack traces, blk-mq debug output etc. but there was nothing in dmesg/on the console, so it wasn't a BUG/OOPS. -h