On Tue, Jan 22, 2019 at 11:32 AM Tetsuo Handa wrote: > > On 2019/01/22 19:12, Dmitry Vyukov wrote: > > On Tue, Jan 22, 2019 at 11:02 AM Tetsuo Handa > > wrote: > >> > >> On 2018/09/22 8:21, Andrew Morton wrote: > >>> On Thu, 20 Sep 2018 19:33:15 -0400 Joel Fernandes wrote: > >>> > >>>> On Thu, Sep 20, 2018 at 5:12 PM Todd Kjos wrote: > >>>>> > >>>>> +Joel Fernandes > >>>>> > >>>>> On Thu, Sep 20, 2018 at 2:11 PM Andrew Morton wrote: > >>>>>> > >>>>>> > >>>>>> Thanks. Let's cc the ashmem folks. > >>>>>> > >>>> > >>>> This should be fixed by https://patchwork.kernel.org/patch/10572477/ > >>>> > >>>> It has Neil Brown's Reviewed-by but looks like didn't yet appear in > >>>> anyone's tree, could Greg take this patch? > >>> > >>> All is well. That went into mainline yesterday, with a cc:stable. > >>> > >> > >> This problem was not fixed at all. > > > > There are at least 2 other open deadlocks involving ashmem: > > Yes, they involve ashmem_shrink_scan() => {shmem|vfs}_fallocate() sequence. > This approach tries to eliminate this sequence. > > > > > https://syzkaller.appspot.com/bug?extid=148c2885d71194f18d28 > > https://syzkaller.appspot.com/bug?extid=4b8b031b89e6b96c4b2e > > > > Does this fix any of these too? > > I need checks from ashmem folks whether this approach is possible/correct. > But you can ask syzbot to test this patch before ashmem folks respond. Right. Let's do this. As with any kernel changes only you really know how to apply it, git tree/base commit info is missing, so let's do guessing and finger-crossing as usual: #syz fix: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master