CVE-2023-53556: In the Linux kernel, the following vulnerability has been resolved:  iavf: Fix use-after-free in free_netdev  We do netif_napi_add() for all allocated q_vectors[], but potentially do netif_napi_del() for part of them, then kfree q_vectors and leave invalid pointers at dev->napi_list.  Reproducer:    [root@host ~]# cat repro.sh   #!/bin/bash    pf_dbsf="0000:41:00.0"   vf0_dbsf="0000:41:02.0"   g_pids=()    function do_set_numvf()   {       echo 2 >/sys/bus/pci/devices/${pf_dbsf}/sriov_numvfs       sleep $((RANDOM%3+1))       echo 0 >/sys/bus/pci/devices/${pf_dbsf}/sriov_numvfs       sleep $((RANDOM%3+1))   }    function do_set_channel()   {       local nic=$(ls -1 --indicator-style=none /sys/bus/pci/devices/${vf0_dbsf}/net/)       [ -z "$nic" ] && { sleep $((RANDOM%3)) ; return 1; }       ifconfig $nic 192.168.18.5 netmask 255.255.255.0       ifconfig $nic up       ethtool -L $nic combined 1       ethtool -L $nic combined 4       sleep $((RANDOM%3))   }    function on_exit()   {       local pid       for pid in "${g_pids[@]}"; do           kill -0 "$pid" &>/dev/null && kill "$pid" &>/dev/null       done       g_pids=()   }    trap "on_exit; exit" EXIT    while :; do do_set_numvf ; done &   g_pids+=($!)   while :; do do_set_channel ; done &   g_pids+=($!)    wait  Result:  [ 4093.900222] ================================================================== [ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390 [ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task repro.sh/6699 [ 4093.900233] [ 4093.900236] CPU: 10 PID: 6699 Comm: repro.sh Kdump: loaded Tainted: G           O     --------- -t - 4.18.0 #1 [ 4093.900238] Hardware name: Powerleader PR2008AL/H12DSi-N6, BIOS 2.0 04/09/2021 [ 4093.900239] Call Trace: [ 4093.900244]  dump_stack+0x71/0xab [ 4093.900249]  print_address_description+0x6b/0x290 [ 4093.900251]  ? free_netdev+0x308/0x390 [ 4093.900252]  kasan_report+0x14a/0x2b0 [ 4093.900254]  free_netdev+0x308/0x390 [ 4093.900261]  iavf_remove+0x825/0xd20 [iavf] [ 4093.900265]  pci_device_remove+0xa8/0x1f0 [ 4093.900268]  device_release_driver_internal+0x1c6/0x460 [ 4093.900271]  pci_stop_bus_device+0x101/0x150 [ 4093.900273]  pci_stop_and_remove_bus_device+0xe/0x20 [ 4093.900275]  pci_iov_remove_virtfn+0x187/0x420 [ 4093.900277]  ? pci_iov_add_virtfn+0xe10/0xe10 [ 4093.900278]  ? pci_get_subsys+0x90/0x90 [ 4093.900280]  sriov_disable+0xed/0x3e0 [ 4093.900282]  ? bus_find_device+0x12d/0x1a0 [ 4093.900290]  i40e_free_vfs+0x754/0x1210 [i40e] [ 4093.900298]  ? i40e_reset_all_vfs+0x880/0x880 [i40e] [ 4093.900299]  ? pci_get_device+0x7c/0x90 [ 4093.900300]  ? pci_get_subsys+0x90/0x90 [ 4093.900306]  ? pci_vfs_assigned.part.7+0x144/0x210 [ 4093.900309]  ? __mutex_lock_slowpath+0x10/0x10 [ 4093.900315]  i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e] [ 4093.900318]  sriov_numvfs_store+0x214/0x290 [ 4093.900320]  ? sriov_totalvfs_show+0x30/0x30 [ 4093.900321]  ? __mutex_lock_slowpath+0x10/0x10 [ 4093.900323]  ? __check_object_size+0x15a/0x350 [ 4093.900326]  kernfs_fop_write+0x280/0x3f0 [ 4093.900329]  vfs_write+0x145/0x440 [ 4093.900330]  ksys_write+0xab/0x160 [ 4093.900332]  ? __ia32_sys_read+0xb0/0xb0 [ 4093.900334]  ? fput_many+0x1a/0x120 [ 4093.900335]  ? filp_close+0xf0/0x130 [ 4093.900338]  do_syscall_64+0xa0/0x370 [ 4093.900339]  ? page_fault+0x8/0x30 [ 4093.900341]  entry_SYSCALL_64_after_hwframe+0x65/0xca [ 4093.900357] RIP: 0033:0x7f16ad4d22c0 [ 4093.900359] Code: 73 01 c3 48 8b 0d d8 cb 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 24 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 fe dd 01 00 48 89 04 24 [ 4093.900360] RSP: 002b:00007ffd6491b7f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 4093.900362] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f16ad4d22c0 [ 4093.900363] RDX: 0000000000000002 RSI: 0000000001a41408 RDI: 0000000000000001 [ 4093.900364] RBP: 0000000001a41408 R08: 00007f16ad7a1780 R09: 00007f16ae1f2700 [ 4093.9003 ---truncated---