On Tue, Jun 18, 2024 at 12:41:37PM +0200, Karol Kolacinski wrote: > From: Jacob Keller <jacob.e.kel...@intel.com> > > The ice_ptp_extts_event() function can race with ice_ptp_release() and > result in a NULL pointer dereference which leads to a kernel panic. > > Panic occurs because the ice_ptp_extts_event() function calls > ptp_clock_event() with a NULL pointer. The ice driver has already > released the PTP clock by the time the interrupt for the next external > timestamp event occurs. > > To fix this, modify the ice_ptp_extts_event() function to check the > PTP state and bail early if PTP is not ready. To ensure that the IRQ > sees the state change, call synchronize_irq() before removing the PTP > clock.
Hi Karol and Jacob, After pf->ptp.state is set in ptp_clock_event(), ice_ptp_disable_all_extts() is called which in turn calls synchronize_irq(). Which I assume is what the last sentence above refers to. But the way it is worded it sounds like a call to synchronize_irq() is being added by this patch, which is not the case. I suppose it is not a big deal, but this did confuse me. So perhaps the wording could be enhanced? > Another potential fix would be to ensure that all the GPIO configuration > gets disabled during release of the driver. This is currently not > trivial as each device family has its own set of configuration which is > not shared across all devices. In addition, only some of the device > families use the pin configuration interface. For now, relying on the > state flag is the simpler solution. > > Fixes: 172db5f91d5f ("ice: add support for auxiliary input/output pins") > Reviewed-by: Przemek Kitszel <przemyslaw.kits...@intel.com> > Signed-off-by: Jacob Keller <jacob.e.kel...@intel.com> > Signed-off-by: Karol Kolacinski <karol.kolacin...@intel.com> > --- > drivers/net/ethernet/intel/ice/ice_ptp.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c > b/drivers/net/ethernet/intel/ice/ice_ptp.c > index 30f1f910e6d9..b952cad42f92 100644 > --- a/drivers/net/ethernet/intel/ice/ice_ptp.c > +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c > @@ -1559,6 +1559,10 @@ void ice_ptp_extts_event(struct ice_pf *pf) > u8 chan, tmr_idx; > u32 hi, lo; > > + /* Don't process timestamp events if PTP is not ready */ > + if (pf->ptp.state != ICE_PTP_READY) > + return; > + > tmr_idx = hw->func_caps.ts_func_info.tmr_index_owned; > /* Event time is captured by one of the two matched registers > * GLTSYN_EVNT_L: 32 LSB of sampled time event > @@ -1573,10 +1577,8 @@ void ice_ptp_extts_event(struct ice_pf *pf) > event.timestamp = (((u64)hi) << 32) | lo; > event.type = PTP_CLOCK_EXTTS; > event.index = chan; > - > - /* Fire event */ > - ptp_clock_event(pf->ptp.clock, &event); > pf->ptp.ext_ts_irq &= ~(1 << chan); > + ptp_clock_event(pf->ptp.clock, &event); > } > } > } I'm also confused (often, TBH!) as to how the last hunk of this patch relates to the problem at hand.