Re: [PATCH net v2 2/2] mac802154: pin netdevs for queued RX descriptors

On 03/09/2026 at 20:32:02 +08, Xuanqiang Luo [off-list ref] wrote:

From: Xuanqiang Luo <redacted>

The RX path keeps the receiving sub-interface in queued beacon and MAC
command descriptors after leaving its RCU read-side critical section. An
interface can therefore be unregistered and freed before mac_wq consumes
the descriptor, leading to a use-after-free such as:

  BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0xc0/0x498 [mac802154]
  Read of size 8 at addr ffff0000c6db0ba8 by task kworker/u16:3/61
  ...
  Call trace:
   show_stack+0x20/0x38 (C)
   dump_stack_lvl+0x78/0x90
   print_address_description.constprop.0+0x88/0x398
   print_report+0xa8/0x278
   kasan_report+0xa8/0xf8
   __asan_load8+0x9c/0xc0
   mac802154_rx_mac_cmd_worker+0xc0/0x498 [mac802154]
   process_one_work+0x334/0x8b8
  ...
  Allocated by task 630:
   kasan_save_stack+0x2c/0x58
   kasan_save_track+0x20/0x40
   kasan_save_alloc_info+0x40/0x58
   __kasan_kmalloc+0xa0/0xb8
   __kvmalloc_node_noprof+0x1e8/0x588
   alloc_netdev_mqs+0x74/0x7f0
   ieee802154_if_add+0xac/0x630 [mac802154]
   ieee802154_register_hw+0x31c/0x3d0 [mac802154]
   fakelb_add_one+0x250/0x318 [fakelb]
  ...
  Freed by task 652:
   kasan_save_stack+0x2c/0x58
   kasan_save_track+0x20/0x40
   kasan_save_free_info+0x4c/0x78
   __kasan_slab_free+0x60/0x90
   kfree+0x194/0x478
   kvfree+0x44/0x60
   netdev_release+0x4c/0x68
   device_release+0xac/0x130
   kobject_cleanup+0x84/0x248
   kobject_put+0x98/0xf8
   netdev_run_todo+0x3a0/0x5e0
   rtnl_unlock+0x18/0x30
   ieee802154_unregister_hw+0x48/0x90 [mac802154]
   fakelb_remove+0xe8/0x148 [fakelb]

Hold the receiving netdev from before a descriptor is queued until the
descriptor is released. Since sdata is the netdev's private data, this also
keeps sdata valid while a worker or scan cleanup accesses the descriptor.

Fixes: 57588c71177f ("mac802154: Handle passive scanning")
Fixes: d021d218f6d9 ("mac802154: Handle received BEACON_REQ")
Cc: stable@vger.kernel.org
Signed-off-by: Xuanqiang Luo <redacted>

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>