On Thu, Jun 28, 2018 at 09:59:38AM -0400, Neil Horman wrote: > On repeated module load/unload cycles, its possible for the pvrmda > driver to encounter this crash: > > ... > 297.032448] RIP: 0010:[<ffffffff839e4620>] [<ffffffff839e4620>] > netdev_walk_all_upper_dev_rcu+0x50/0xb0 > [ 297.034078] RSP: 0018:ffff95087780bd08 EFLAGS: 00010286 > [ 297.034986] RAX: 0000000000000000 RBX: 0000000000000000 RCX: > ffff95087a0c0000 > [ 297.036196] RDX: ffff95087a0c0000 RSI: ffffffff839e44e0 RDI: > ffff950835d0c000 > [ 297.037421] RBP: ffff95087780bd40 R08: ffff95087a0e0ea0 R09: > abddacd03f8e0ea0 > [ 297.038636] R10: abddacd03f8e0ea0 R11: ffffef5901e9dbc0 R12: > ffff95087a0c0000 > [ 297.039854] R13: ffffffff839e44e0 R14: ffff95087a0c0000 R15: > ffff950835d0c828 > [ 297.041071] FS: 0000000000000000(0000) GS:ffff95087fc00000(0000) > knlGS:0000000000000000 > [ 297.042443] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 297.043429] CR2: ffffffffffffffe8 CR3: 000000007a652000 CR4: > 00000000003607f0 > [ 297.044674] DR0: 0000000000000000 DR1: 0000000000000000 DR2: > 0000000000000000 > [ 297.045893] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: > 0000000000000400 > [ 297.047109] Call Trace: > [ 297.047545] [<ffffffff839e4698>] netdev_has_upper_dev_all_rcu+0x18/0x20 > [ 297.048691] [<ffffffffc05d31af>] is_eth_port_of_netdev+0x2f/0xa0 [ib_core] > [ 297.049886] [<ffffffffc05d3180>] ? > is_eth_active_slave_of_bonding_rcu+0x70/0x70 [ib_core] > ... > > This occurs because vmw_pvrdma on probe stores a pointer to the netdev > that exists on function 0 of the same bus/device/slot (which represents > the vmxnet3 ethernet driver). However, it never removes this pointer if > the vmxnet3 module is removed, leading to crashes resulting from use > after free dereferencing incidents like the one above. > > The fix is pretty straightforward. vmw_pvrdma should listen for > NETDEV_REGISTER and NETDEV_UNREGISTER events in its event listener code > block, and update the stored netdev pointer accordingly. This solution > has been tested by myself and the reporter with successful results. > This fix also allows the pvrdma driver to find its underlying ethernet > device in the event that vmxnet3 is loaded after pvrdma, which it was > not able to do before. > > Signed-off-by: Neil Horman <nhor...@tuxdriver.com> > Reported-by: ruq...@redhat.com > CC: Adit Ranadive <ad...@vmware.com> > CC: VMware PV-Drivers <pv-driv...@vmware.com> > CC: Doug Ledford <dledf...@redhat.com> > CC: Jason Gunthorpe <j...@ziepe.ca> > CC: linux-kernel@vger.kernel.org > .../infiniband/hw/vmw_pvrdma/pvrdma_main.c | 25 +++++++++++++++++-- > 1 file changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/hw/vmw_pvrdma/pvrdma_main.c > b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_main.c > index 0be33a81bbe6..5b4782078a74 100644 > +++ b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_main.c > @@ -699,8 +699,12 @@ static int pvrdma_del_gid(const struct ib_gid_attr > *attr, void **context) > } > > static void pvrdma_netdevice_event_handle(struct pvrdma_dev *dev, > + struct net_device *ndev, > unsigned long event) > { > + struct pci_dev *pdev_net; > + > + > switch (event) { > case NETDEV_REBOOT: > case NETDEV_DOWN: > @@ -718,6 +722,21 @@ static void pvrdma_netdevice_event_handle(struct > pvrdma_dev *dev, > else > pvrdma_dispatch_event(dev, 1, IB_EVENT_PORT_ACTIVE); > break; > + case NETDEV_UNREGISTER: > + dev_put(dev->netdev); > + dev->netdev = NULL; > + break; > + case NETDEV_REGISTER: > + /* Paired vmxnet3 will have same bus, slot. But func will be 0 > */ > + pdev_net = pci_get_slot(dev->pdev->bus, > PCI_DEVFN(PCI_SLOT(dev->pdev->devfn), 0)); > + if ((dev->netdev == NULL) && (pci_get_drvdata(pdev_net) == > ndev)) { > + /* this is our netdev */ > + dev->netdev = ndev; > + dev_hold(ndev); > + } > + pci_dev_put(pdev_net); > + break; > + > default: > dev_dbg(&dev->pdev->dev, "ignore netdevice event %ld on %s\n", > event, dev->ib_dev.name); > @@ -734,8 +753,9 @@ static void pvrdma_netdevice_event_work(struct > work_struct *work) > > mutex_lock(&pvrdma_device_list_lock); > list_for_each_entry(dev, &pvrdma_device_list, device_link) { > - if (dev->netdev == netdev_work->event_netdev) { > - pvrdma_netdevice_event_handle(dev, netdev_work->event); > + if ((netdev_work->event == NETDEV_REGISTER) || > + (dev->netdev == netdev_work->event_netdev)) { > + pvrdma_netdevice_event_handle(dev, > netdev_work->event_netdev, netdev_work->event); > break; > } > } > @@ -962,6 +982,7 @@ static int pvrdma_pci_probe(struct pci_dev *pdev, > } > > dev->netdev = pci_get_drvdata(pdev_net); > + dev_hold(dev->netdev); > pci_dev_put(pdev_net); > if (!dev->netdev) { > dev_err(&pdev->dev, "failed to get vmxnet3 device\n");
I see a lot of new dev_hold's here, where are the matching dev_puts()? Jason