On Thu, 22 Oct 2015, Minchan Kim wrote: > > I added the code to check it and queued it again but I had another oops > in this time but symptom is related to anon_vma, too. > (kernel is based on recent mmotm + unconditional mkdirty for bug fix) > It seems page_get_anon_vma returns NULL since the page was not page_mapped > at that time but second check of page_mapped right before try_to_unmap seems > to be true. > > Adding 4191228k swap on /dev/vda5. Priority:-1 extents:1 across:4191228k FS > Adding 4191228k swap on /dev/vda5. Priority:-1 extents:1 across:4191228k FS > page:ffffea0001cfbfc0 count:3 mapcount:1 mapping:ffff88007f1b5f51 index:0x600000aff > flags: 0x4000000000048019(locked|uptodate|dirty|swapcache|swapbacked) > page dumped because: VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma) That's interesting, that's one I added in my page migration series. Let me think on it, but it could well relate to the one you got before. > page->mem_cgroup:ffff88007f3dcc00 > ------------[ cut here ]------------ > kernel BUG at mm/migrate.c:889! > invalid opcode: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 11 PID: 59 Comm: khugepaged Not tainted 4.3.0-rc6-next-20151021-THP-ref-madv_free+ #1557 Hmm, it might be me to blame, or it might be Kirill, don't know yet. Oh, hold on, I think Andrew has just posted a new mmotm, and it includes an update to Kirill's migrate_pages-try-to-split-pages-on-queueing.patch: I haven't digested yet, but it might turn out to be relevant. Hugh -- 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>