[PATCH iwl-net] idpf: fix possible race on remove during a reset

[Emil Tantilov <emil.s.tantilov@intel.com>]

Reset and remove can race, leaving NAPI registered and enabled:

modprobe idpf& sleep 1; ip link set eth0 up& rmmod idpf

[145561.805104] WARNING: net/core/dev.c:7699 at __netif_napi_del_locked+0x11a/0x130, CPU#30: rmmod/22393
...
[145561.810238] RIP: 0010:__netif_napi_del_locked+0x11a/0x130
...
[145561.817678] Call Trace:
[145561.818125]  <TASK>
[145561.818653]  free_netdev+0x110/0x2a0
[145561.819109]  idpf_vport_dealloc+0x452/0x460 [idpf]
[145561.819668]  ? enable_work+0x9f/0x100
[145561.820133]  idpf_deinit_task+0x51/0x70 [idpf]
[145561.820694]  idpf_vc_core_deinit+0x32/0x170 [idpf]
[145561.821193]  idpf_remove+0x40/0x200 [idpf]
[145561.821667]  pci_device_remove+0x40/0xa0
[145561.822132]  device_release_driver_internal+0x1a9/0x210
[145561.822691]  driver_detach+0x4b/0x90
[145561.823161]  bus_remove_driver+0x70/0x100
[145561.823721]  pci_unregister_driver+0x2e/0xb0
[145561.824207]  __do_sys_delete_module.constprop.0+0x190/0x2e0
[145561.824715]  ? kmem_cache_free+0x312/0x550
[145561.825213]  do_syscall_64+0xc8/0x6b0
[145561.825709]  ? clear_bhb_loop+0x30/0x80
[145561.826216]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[145561.826602] RIP: 0033:0x7fe628130beb

Make sure to call idpf_vport_stop() in idpf_stop(), irrespective of the
IDPF_REMOVE_IN_PROG state, to allow a reset racing with remove to tear
down NAPI in idpf_detach_and_close(), which runs under RTNL lock.

Fixes: 2e281e1155fc ("idpf: detach and close netdevs while handling a reset")
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Reviewed-by: Joshua Hay <joshua.a.hay@intel.com>
---
 drivers/net/ethernet/intel/idpf/idpf_lib.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_lib.c b/drivers/net/ethernet/intel/idpf/idpf_lib.c
index bb81e620c5c8..c2d7d92d0bf1 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_lib.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_lib.c
@@ -1031,12 +1031,8 @@ static void idpf_vport_stop(struct idpf_vport *vport, bool rtnl)
  */
 static int idpf_stop(struct net_device *netdev)
 {
-	struct idpf_netdev_priv *np = netdev_priv(netdev);
 	struct idpf_vport *vport;
 
-	if (test_bit(IDPF_REMOVE_IN_PROG, np->adapter->flags))
-		return 0;
-
 	idpf_vport_ctrl_lock(netdev);
 	vport = idpf_netdev_to_vport(netdev);
 
-- 
2.37.3