Hi, On Thu, Sep 20, 2018 at 10:25:01AM -0400, Mikulas Patocka wrote: > > > On Wed, 19 Sep 2018, Dmitry Safonov wrote: > > > On Wed, 2018-09-19 at 16:03 -0400, Mikulas Patocka wrote: > > > > > > On Wed, 19 Sep 2018, Dmitry Safonov wrote: > > > > Thanks much for the testing, Mikulas. > > > > Could you try to bisect which of the patches causes it? > > > > The most important are 1,2,3 - probably, one of them caused it.. > > > > I'll stare a bit into the code. > > > > > > The patch 3 causes it. > > > > > > The hangs during reboot take either 80 seconds, 3 minutes or 3:25. > > > > Thanks much for that again. > > Any chance you have sysrq enabled and could print: locks held in system > > and kernel backtraces for applications? > > Stacktrace doesn't work on parisc. It used to work on 4.18, but the kernel > 4.19 reportedly requires patched binutils. > > Mikulas > > > I suppose, userspace hangs in n_tty_receive_buf_common(), which is > > better of cause than null-ptr dereference, but I believe we can improve > > it by stopping a reader earlier if there is any writer pending. > > > > -- > > Thanks, > > Dmitry > > Any progress here? Or is more info/stacktrace needed about the hang? Thanks, -- Pasi
