In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Fix netif state handling

mlx5e_suspend cleans resources only if netif_device_present() returns
true. However, mlx5e_resume changes the state of netif, via
mlx5e_nic_enable, only if reg_state == NETREG_REGISTERED.
In the below case, the above leads to NULL-ptr Oops[1] and memory
leaks:

mlx5e_probe
_mlx5e_resume
mlx5e_attach_netdev
mlx5e_nic_enable <— netdev not reg, not calling netif_device_attach()
register_netdev <— failed for some reason.
ERROR_FLOW:
_mlx5e_suspend <— netif_device_present return false, resources aren’t freed :(

Hence, clean resources in this case as well.

[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: 0010 [#1] SMP
CPU: 2 PID: 9345 Comm: test-ovs-ct-gen Not tainted 6.5.0_for_upstream_min_debug_2023_09_05_16_01 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at0xffffffffffffffd6.
RSP: 0018:ffff888178aaf758 EFLAGS: 00010246
Call Trace:
<TASK>
? __die+0x20/0x60
? page_fault_oops+0x14c/0x3c0
? exc_page_fault+0x75/0x140
? asm_exc_page_fault+0x22/0x30
notifier_call_chain+0x35/0xb0
blocking_notifier_call_chain+0x3d/0x60
mlx5_blocking_notifier_call_chain+0x22/0x30 [mlx5_core]
mlx5_core_uplink_netdev_event_replay+0x3e/0x60 [mlx5_core]
mlx5_mdev_netdev_track+0x53/0x60 [mlx5_ib]
mlx5_ib_roce_init+0xc3/0x340 [mlx5_ib]
__mlx5_ib_add+0x34/0xd0 [mlx5_ib]
mlx5r_probe+0xe1/0x210 [mlx5_ib]
? auxiliary_match_id+0x6a/0x90
auxiliary_bus_probe+0x38/0x80
? driver_sysfs_add+0x51/0x80
really_probe+0xc9/0x3e0
? driver_probe_device+0x90/0x90
__driver_probe_device+0x80/0x160
driver_probe_device+0x1e/0x90
__device_attach_driver+0x7d/0x100
bus_for_each_drv+0x80/0xd0
__device_attach+0xbc/0x1f0
bus_probe_device+0x86/0xa0
device_add+0x637/0x840
__auxiliary_device_add+0x3b/0xa0
add_adev+0xc9/0x140 [mlx5_core]
mlx5_rescan_drivers_locked+0x22a/0x310 [mlx5_core]
mlx5_register_device+0x53/0xa0 [mlx5_core]
mlx5_init_one_devl_locked+0x5c4/0x9c0 [mlx5_core]
mlx5_init_one+0x3b/0x60 [mlx5_core]
probe_one+0x44c/0x730 [mlx5_core]
local_pci_probe+0x3e/0x90
pci_device_probe+0xbf/0x210
? kernfs_create_link+0x5d/0xa0
? sysfs_do_create_link_sd+0x60/0xc0
really_probe+0xc9/0x3e0
? driver_probe_device+0x90/0x90
__driver_probe_device+0x80/0x160
driver_probe_device+0x1e/0x90
__device_attach_driver+0x7d/0x100
bus_for_each_drv+0x80/0xd0
__device_attach+0xbc/0x1f0
pci_bus_add_device+0x54/0x80
pci_iov_add_virtfn+0x2e6/0x320
sriov_enable+0x208/0x420
mlx5_core_sriov_configure+0x9e/0x200 [mlx5_core]
sriov_numvfs_store+0xae/0x1a0
kernfs_fop_write_iter+0x10c/0x1a0
vfs_write+0x291/0x3c0
ksys_write+0x5f/0xe0
do_syscall_64+0x3d/0x90
entry_SYSCALL_64_after_hwframe+0x46/0xb0
CR2: 0000000000000000
—–[ end trace 0000000000000000 ]—-