| Message ID | 20240618104310.1429515-3-karol.kolacinski@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ice: Fix incorrect input/output pin behavior | expand |
On Tue, Jun 18, 2024 at 12:41:37PM +0200, Karol Kolacinski wrote: > From: Jacob Keller <jacob.e.keller@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.kitszel@intel.com> > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > Signed-off-by: Karol Kolacinski <karol.kolacinski@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.
> -----Original Message----- > From: Simon Horman <horms@kernel.org> > Sent: Wednesday, June 19, 2024 9:41 AM > To: Kolacinski, Karol <karol.kolacinski@intel.com> > Cc: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; Nguyen, Anthony L > <anthony.l.nguyen@intel.com>; Kitszel, Przemyslaw > <przemyslaw.kitszel@intel.com>; Keller, Jacob E <jacob.e.keller@intel.com> > Subject: Re: [PATCH iwl-net 2/3] ice: Don't process extts if PTP is disabled > > On Tue, Jun 18, 2024 at 12:41:37PM +0200, Karol Kolacinski wrote: > > From: Jacob Keller <jacob.e.keller@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? > I believe the call to synchronize_irq() predates this as the same IRQ is used for other timestamping/PTP related events. This could be clarified in the commit message > > 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.kitszel@intel.com> > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > > Signed-off-by: Karol Kolacinski <karol.kolacinski@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.
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); } } }