[PATCH net-next v1 03/21] liquidio: Overcome missing device lock protection in init/remove flows
From: Leon Romanovsky <leon@kernel.org>
Date: 2021-09-25 11:23:39
Also in:
intel-wired-lan, linux-omap, linux-rdma, lkml, netdev
Subsystem:
cavium liquidio network driver, networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Leon Romanovsky <leonro@nvidia.com> The liquidio driver is broken by design. It initialize PCI devices in separate delayed works. It causes to the situation where device lock is dropped during initialize and remove sequences. That lock is part of driver/core and needed to protect from races during init, destroy and bus invocations. In addition to lack of locking protection, it has incorrect order of destroy flows and very questionable synchronization scheme based on atomic_t. This change doesn't fix that driver but makes sure that rest of the netdev subsystem doesn't suffer from such basic protection by adding device_lock over devlink_*() APIs and by moving devlink_register() to be last command in setup_nic_devices(). Signed-off-by: Leon Romanovsky <leonro@nvidia.com> --- .../net/ethernet/cavium/liquidio/lio_main.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index a34b3bb2dd4f..dafc79bd34f4 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c@@ -1279,6 +1279,14 @@ static int liquidio_stop_nic_module(struct octeon_device *oct) struct lio *lio; dev_dbg(&oct->pci_dev->dev, "Stopping network interfaces\n"); + device_lock(&oct->pci_dev->dev); + if (oct->devlink) { + devlink_unregister(oct->devlink); + devlink_free(oct->devlink); + oct->devlink = NULL; + } + device_unlock(&oct->pci_dev->dev); + if (!oct->ifcount) { dev_err(&oct->pci_dev->dev, "Init for Octeon was not completed\n"); return 1;
@@ -1300,12 +1308,6 @@ static int liquidio_stop_nic_module(struct octeon_device *oct) for (i = 0; i < oct->ifcount; i++) liquidio_destroy_nic_device(oct, i); - if (oct->devlink) { - devlink_unregister(oct->devlink); - devlink_free(oct->devlink); - oct->devlink = NULL; - } - dev_dbg(&oct->pci_dev->dev, "Network interfaces stopped\n"); return 0; }
@@ -3749,10 +3751,12 @@ static int setup_nic_devices(struct octeon_device *octeon_dev) } } + device_lock(&octeon_dev->pci_dev->dev); devlink = devlink_alloc(&liquidio_devlink_ops, sizeof(struct lio_devlink_priv), &octeon_dev->pci_dev->dev); if (!devlink) { + device_unlock(&octeon_dev->pci_dev->dev); dev_err(&octeon_dev->pci_dev->dev, "devlink alloc failed\n"); goto setup_nic_dev_free; }
@@ -3760,9 +3764,10 @@ static int setup_nic_devices(struct octeon_device *octeon_dev) lio_devlink = devlink_priv(devlink); lio_devlink->oct = octeon_dev; - devlink_register(devlink); octeon_dev->devlink = devlink; octeon_dev->eswitch_mode = DEVLINK_ESWITCH_MODE_LEGACY; + devlink_register(devlink); + device_unlock(&octeon_dev->pci_dev->dev); return 0;
--
2.31.1