On Thu, Mar 07, 2019 at 10:16:17PM -0800, Dan Williams wrote: > Hi Willy, > > We're seeing a case where RocksDB hangs and becomes defunct when > trying to kill the process. v4.19 succeeds and v4.20 fails. Robert was > able to bisect this to commit b15cd800682f "dax: Convert page fault > handlers to XArray". > > I see some direct usage of xa_index and wonder if there are some more > pmd fixups to do? > > Other thoughts? I don't see why killing a process would have much to do with PMD misalignment. The symptoms (hanging on a signal) smell much more like leaving a locked entry in the tree. Is this easy to reproduce? Can you get /proc/$pid/stack for a hung task?
