RE: [Intel-wired-lan] [PATCH v3 net] idpf: disable PTM on probe failure and on remove

[Salin, Samuel]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of
> Myeonghun Pak
> Sent: Saturday, July 25, 2026 6:55 AM
> To: Loktionov, Aleksandr <aleksandr.loktionov@xxxxxxxxx>
> Cc: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@xxxxxxxxx>; intel-wired-lan@xxxxxxxxxxxxxxxx; Olech,
> Milena <milena.olech@xxxxxxxxx>; Tantilov, Emil S
> <emil.s.tantilov@xxxxxxxxx>; Mina Almasry <almasrymina@xxxxxxxxxx>;
> Andrew Lunn <andrew+netdev@xxxxxxx>; David S . Miller
> <davem@xxxxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub
> Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>;
> netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Ijae Kim
> <ae878000@xxxxxxxxx>
> Subject: Re: [Intel-wired-lan] [PATCH v3 net] idpf: disable PTM on probe
> failure and on remove
> 
> Understood. I won’t repost it unless I receive concrete feedback.
> 
> Thanks for the clarification.
> 
> Best regards,
> Myeonghun Park
> 
> 2026년 7월 23일 (목) 오후 6:17, Loktionov, Aleksandr
> <aleksandr.loktionov@xxxxxxxxx>님이 작성:
> >
> >
> >
> > > -----Original Message-----
> > > From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> > > Of Myeonghun Pak
> > > Sent: Monday, July 20, 2026 4:35 PM
> > > To: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel,
> > > Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; intel-wired-
> > > lan@xxxxxxxxxxxxxxxx
> > > Cc: Olech, Milena <milena.olech@xxxxxxxxx>; Tantilov, Emil S
> > > <emil.s.tantilov@xxxxxxxxx>; Mina Almasry <almasrymina@xxxxxxxxxx>;
> > > Andrew Lunn <andrew+netdev@xxxxxxx>; David S . Miller
> > > <davem@xxxxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub
> > > Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>;
> > > netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Myeonghun Pak
> > > <mhun512@xxxxxxxxx>; Ijae Kim <ae878000@xxxxxxxxx>
> > > Subject: [Intel-wired-lan] [PATCH v3 net] idpf: disable PTM on probe
> > > failure and on remove
> > >
> > > idpf_probe() enables PCIe Precision Time Measurement with
> > > pci_enable_ptm(), which takes a reference on the device and on every
> > > PTM-capable device up the path to the PTM Root.
> > >
> > > Neither the probe error path nor idpf_remove() drops that reference,
> > > so the PTM enable counts of this device and of its upstream path
> > > stay elevated with no bound driver, and the device's PTM control
> > > bits remain set.  pcim_enable_device() only arranges for
> > > pci_disable_device() and does not undo the PTM enable.
> > >
> > > Add the matching pci_disable_ptm() to the common probe unwind and to
> > > idpf_remove().  pci_enable_ptm() failure is not fatal here, so guard
> > > both calls with pcie_ptm_enabled(): pci_disable_ptm() decrements
> > > dev->ptm_enable_cnt unconditionally and then recurses upstream, so
> > > calling it after a failed enable would drive this device's count
> > > negative and wrongly decrement parents shared with other endpoints.
> > >
> > > This issue was identified during our ongoing static-analysis
> > > research while reviewing kernel code.
> > >
> > > Fixes: 8d5e12c5921c ("idpf: add initial PTP support")
> > > Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
> > > Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
> > > Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
> > > ---
> > > Changes in v3:
> > > - Rebased; aa8671af0c38 ("PCI/PTM: Drop pci_enable_ptm() granularity
> > >   parameter") changed the call signature, so v2 no longer applied.
> > > - Guard both pci_disable_ptm() calls with pcie_ptm_enabled(), as
> > >   pci_disable_ptm() is refcounted and recurses upstream since
> > >   e1092d5e15e6 ("PCI/PTM: Do not enable PTM automatically for Root
> and
> > >   Switch Upstream Ports").  Raised by Tony Nguyen.
> > > - Dropped the v2 claim that pci_disable_ptm() is a no-op when PTM
> > > was not
> > >   enabled; that is no longer true.
> > >
> > > Changes in v2:
> > > - Disable PTM in the probe error path, as requested by Emil Tantilov.
> > >
> > >  drivers/net/ethernet/intel/idpf/idpf_main.c | 9 +++++++--
> > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/intel/idpf/idpf_main.c
> > > b/drivers/net/ethernet/intel/idpf/idpf_main.c
> > > index ab3c409..97bafeb 100644
> > > --- a/drivers/net/ethernet/intel/idpf/idpf_main.c
> > > +++ b/drivers/net/ethernet/intel/idpf/idpf_main.c
> > > @@ -159,6 +159,8 @@ destroy_wqs:
> > >       mutex_destroy(&adapter->queue_lock);
> > >       mutex_destroy(&adapter->vc_buf_lock);
> > >
> > > +     if (pcie_ptm_enabled(pdev))
> > > +             pci_disable_ptm(pdev);
> > >       pci_set_drvdata(pdev, NULL);
> > >       kfree(adapter);
> > >  }
> > > @@ -266,7 +268,7 @@ static int idpf_probe(struct pci_dev *pdev,
> > > const struct pci_device_id *ent)
> > >       if (err) {
> > >               pci_err(pdev, "DMA configuration failed: %pe\n",
> > > ERR_PTR(err));
> > >
> > > -             goto err_free;
> > > +             goto err_disable_ptm;
> > >       }
> > >
> > >       pci_set_master(pdev);
> > > @@ -279,7 +281,7 @@ static int idpf_probe(struct pci_dev *pdev,
> > > const struct pci_device_id *ent)
> > >       if (!adapter->init_wq) {
> > >               dev_err(dev, "Failed to allocate init workqueue\n");
> > >               err = -ENOMEM;
> > > -             goto err_free;
> > > +             goto err_disable_ptm;
> > >       }
> > >
> > >       adapter->serv_wq = alloc_workqueue("%s-%s-service", @@ -366,6
> > > +368,9 @@ err_mbx_wq_alloc:
> > >       destroy_workqueue(adapter->serv_wq);
> > >  err_serv_wq_alloc:
> > >       destroy_workqueue(adapter->init_wq);
> > > +err_disable_ptm:
> > > +     if (pcie_ptm_enabled(pdev))
> > > +             pci_disable_ptm(pdev);
> > >  err_free:
> > >       kfree(adapter);
> > >       return err;
> > > --
> > > 2.47.1
> >
> > Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>

Tested-by: Samuel Salin <Samuel.salin@xxxxxxxxx>