On Thu 20-10-16 23:39:39, Brian Norris wrote: > (Preface: this wasn't a clean backport, I'm a bit under the weather, and > it's getting late here. So forgive me if my head's not on straight.) > > Hi, > > I'm not sure the best way to report this, but the Chrome OS test > infrastructure noticed some problems when testing the following patch > backported to our 3.8 kernels: > > http://www.spinics.net/lists/stable/msg147998.html > > Specifically (if you can hold your nose and stand Gerrit), this change: > > https://chromium-review.googlesource.com/#/c/401041/
This is not correct. You have https://chromium-review.googlesource.com/#/c/401041/2/mm/memory.c f ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, page, flags)) { pte_unmap_unlock(ptep, ptl); goto no_page; } so you do a double unlock. See how my patch does + if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, page, flags)) { + pte_unmap_unlock(ptep, ptl); + return NULL; + } -- Michal Hocko SUSE Labs
