On Thu, Aug 20, 2020 at 01:43:05PM -0700, Andrew Morton wrote: > On Fri, 21 Aug 2020 04:26:12 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > > > tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > branch HEAD: 605cbf3d5f20470ec303b79feda3202935f4a142 Add linux-next specific files for 20200820 > > > > Error/Warning in current branch: > > > ... > > > > > > fs/proc/task_mmu.c:947 show_smaps_rollup() error: double unlocked 'mm->mmap_lock' (orig line 879) > > This is code added by "mm: proc: smaps_rollup: do not stall write > attempts on mmap_lock" > (http://lkml.kernel.org/r/1597715898-3854-4-git-send-email-chinwen.chang@xxxxxxxxxxxx). > > I don't get it. Sorry Andrew, this is a false positive. We wrongly send out a few false reports related to "double unlocked" due to bot issue. Sorry for the inconvenience caused. > > : if (mmap_lock_is_contended(mm)) { > : mmap_read_unlock(mm); > : ret = mmap_read_lock_killable(mm); > : if (ret) { > : release_task_mempolicy(priv); > : goto out_put_mm; > : } > > Here the mmap_lock is again taken for read > > : ... > : > : } > : /* Case 2 above */ > : vma = vma->vm_next; > : } > : > : ... > : > : mmap_read_unlock(mm); > > and here it's unlocked. I don't see a possibility for double-unlock? >
