> From: Intel-wired-lan [mailto:intel-wired-lan-boun...@lists.osuosl.org] On > Behalf Of Denys Vlasenko > Sent: Friday, May 6, 2016 12:42 PM > To: Kirsher, Jeffrey T <jeffrey.t.kirs...@intel.com> > Cc: intel-wired-...@lists.osuosl.org; Denys Vlasenko > <dvlas...@redhat.com>; LKML <linux-ker...@vger.kernel.org>; > netdev@vger.kernel.org > Subject: [Intel-wired-lan] [PATCH] e1000e: prevent division by zero if > TIMINCA is zero > > Users report that under VMWare, er32(TIMINCA) returns zero. > This causes division by zero at init time as follows: > > ==> incvalue = er32(TIMINCA) & E1000_TIMINCA_INCVALUE_MASK; > for (i = 0; i < E1000_MAX_82574_SYSTIM_REREADS; i++) { > /* latch SYSTIMH on read of SYSTIML */ > systim_next = (cycle_t)er32(SYSTIML); > systim_next |= (cycle_t)er32(SYSTIMH) << 32; > > time_delta = systim_next - systim; > temp = time_delta; > ====> rem = do_div(temp, incvalue); > > This change makes kernel survive this, and users report that > NIC does work after this change. > > Since on real hardware incvalue is never zero, this should not affect > real hardware use case. > > Signed-off-by: Denys Vlasenko <dvlas...@redhat.com> > CC: Jeff Kirsher <jeffrey.t.kirs...@intel.com> > CC: "Ruinskiy, Dima" <dima.ruins...@intel.com> > CC: intel-wired-...@lists.osuosl.org > CC: netdev@vger.kernel.org > CC: LKML <linux-ker...@vger.kernel.org> > --- > drivers/net/ethernet/intel/e1000e/netdev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-)
As Mark Rustad pointed out I recall this was earlier rejected as something that is a VMWare error and it should be fixed there so that existing VMs will start working without installing a new driver. Having said that, it does not seem to be causing any harm in my testing, so... Tested-by: Aaron Brown <aaron.f.br...@intel.com>
