idpf: clear stale cdev_info ptr

Deinit calls idpf_idc_deinit_core_aux_device to free the cdev_info
memory, but leaves the adapter->cdev_info field with a stale pointer
value. This will bypass subsequent "if (!cdev_info)" checks if cdev_info
is not reallocated. For example, if idc_init fails after a reset,
cdev_info will already have been freed during the reset handling, but it
will not have been reallocated. The next reset or rmmod will result in a
crash.

[  +0.000008] BUG: kernel NULL pointer dereference, address: 00000000000000d0
[  +0.000033] #PF: supervisor read access in kernel mode
[  +0.000020] #PF: error_code(0x0000) - not-present page
[  +0.000017] PGD 2097dfa067 P4D 0
[  +0.000017] Oops: Oops: 0000 [#1] SMP NOPTI
...
[  +0.000018] RIP: 0010:device_del+0x3e/0x3d0
[  +0.000010] Call Trace:
[  +0.000010]  <TASK>
[  +0.000012]  idpf_idc_deinit_core_aux_device+0x36/0x70 [idpf]
[  +0.000034]  idpf_vc_core_deinit+0x3e/0x180 [idpf]
[  +0.000035]  idpf_remove+0x40/0x1d0 [idpf]
[  +0.000035]  pci_device_remove+0x42/0xb0
[  +0.000020]  device_release_driver_internal+0x19c/0x200
[  +0.000024]  driver_detach+0x48/0x90
[  +0.000018]  bus_remove_driver+0x6d/0x100
[  +0.000023]  pci_unregister_driver+0x2e/0xb0
[  +0.000022]  __do_sys_delete_module.isra.0+0x18c/0x2b0
[  +0.000025]  ? kmem_cache_free+0x2c2/0x390
[  +0.000023]  do_syscall_64+0x107/0x7d0
[  +0.000023]  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Pass the adapter struct into idpf_idc_deinit_core_aux_device instead and
clear the cdev_info ptr.

Fixes: f4312e6 ("idpf: implement core RDMA auxiliary dev create, init, and destroy")
Signed-off-by: Joshua Hay <[email protected]>
Reviewed-by: Przemek Kitszel <[email protected]>
Reviewed-by: Aleksandr Loktionov <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Tested-by: Samuel Salin <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: jahay1

drivers/net/ethernet/intel/idpf/idpf.h

@@ -1066,7 +1066,7 @@ bool idpf_vport_set_hsplit(const struct idpf_vport *vport, u8 val);
 int idpf_idc_init(struct idpf_adapter *adapter);
 int idpf_idc_init_aux_core_dev(struct idpf_adapter *adapter,
 			       enum iidc_function_type ftype);
-void idpf_idc_deinit_core_aux_device(struct iidc_rdma_core_dev_info *cdev_info);
+void idpf_idc_deinit_core_aux_device(struct idpf_adapter *adapter);
 void idpf_idc_deinit_vport_aux_device(struct iidc_rdma_vport_dev_info *vdev_info);
 void idpf_idc_issue_reset_event(struct iidc_rdma_core_dev_info *cdev_info);
 void idpf_idc_vdev_mtu_event(struct iidc_rdma_vport_dev_info *vdev_info,

drivers/net/ethernet/intel/idpf/idpf_idc.c

@@ -470,10 +470,11 @@ int idpf_idc_init_aux_core_dev(struct idpf_adapter *adapter,
 
 /**
  * idpf_idc_deinit_core_aux_device - de-initialize Auxiliary Device(s)
- * @cdev_info: IDC core device info pointer
+ * @adapter: driver private data structure
  */
-void idpf_idc_deinit_core_aux_device(struct iidc_rdma_core_dev_info *cdev_info)
+void idpf_idc_deinit_core_aux_device(struct idpf_adapter *adapter)
 {
+	struct iidc_rdma_core_dev_info *cdev_info = adapter->cdev_info;
 	struct iidc_rdma_priv_dev_info *privd;
 
 	if (!cdev_info)
@@ -485,6 +486,7 @@ void idpf_idc_deinit_core_aux_device(struct iidc_rdma_core_dev_info *cdev_info)
 	kfree(privd->mapped_mem_regions);
 	kfree(privd);
 	kfree(cdev_info);
+	adapter->cdev_info = NULL;
 }
 
 /**

drivers/net/ethernet/intel/idpf/idpf_virtchnl.c

@@ -3668,7 +3668,7 @@ void idpf_vc_core_deinit(struct idpf_adapter *adapter)
 
 	idpf_ptp_release(adapter);
 	idpf_deinit_task(adapter);
-	idpf_idc_deinit_core_aux_device(adapter->cdev_info);
+	idpf_idc_deinit_core_aux_device(adapter);
 	idpf_rel_rx_pt_lkup(adapter);
 	idpf_intr_rel(adapter);