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 <nhorman@xxxxxxxxxxxxx>
> Reported-by: ruquin@xxxxxxxxxx
> CC: Adit Ranadive <aditr@xxxxxxxxxx>
> CC: VMware PV-Drivers <pv-drivers@xxxxxxxxxx>
> CC: Doug Ledford <dledford@xxxxxxxxxx>
> CC: Jason Gunthorpe <jgg@xxxxxxxx>
> CC: linux-kernel@xxxxxxxxxxxxxxx
> .../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
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