On Thu 24-12-15 20:06:50, Tetsuo Handa wrote: > Michal Hocko wrote: > > This is VM_BUG_ON_PAGE(page_mapped(page), page), right? Could you attach > > the full kernel log? It all smells like a race when OOM reaper tears > > down the mapping and there is a truncate still in progress. But hitting > > the BUG_ON just because of that doesn't make much sense to me. OOM > > reaper is essentially MADV_DONTNEED. I have to think about this some > > more, though, but I am in a holiday mode until early next year so please > > bear with me. > > I don't know whether the OOM killer was invoked just before this > VM_BUG_ON_PAGE(). > > > Is this somehow DAX related? > > 4.4.0-rc6-next-20151223_new_fsync_v6+ suggests that this kernel > has "[PATCH v6 0/7] DAX fsync/msync support" applied. But I think > http://marc.info/?l=linux-mm&m=145068666428057 should be applied > when retesting. (20151223 does not have this fix.) Hmm, I think you are right! Very well spotted! If ignore_dirty ends up being true then we would simply skip over dirty page and wouldn't end up doing page_remove_rmap. I can see that the truncation code can later trip over this page. Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>