Re: [PATCH net v1] mac802154: drain mac_wq before unregistering interfaces

在 2026/8/31 16:10, Miquel Raynal 写道:

On 28/08/2026 at 18:19:05 +08, Xuanqiang Luo [off-list ref] wrote:

quoted

From: Xuanqiang Luo <redacted>

ieee802154_unregister_hw() unregisters the wpan netdevs before
destroying mac_wq. The RX path stores the receiving sub-interface
(sdata) in the queued MAC command descriptor without taking a
reference to the netdev.

If mac802154_rx_mac_cmd_worker() runs after the netdev has been freed,
it dereferences the stale pointer and triggers a KASAN
slab-use-after-free:

   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]

After killing local->tasklet, drain mac_wq before calling
ieee802154_remove_interfaces() so pending work completes before the
interfaces are unregistered. Do this without holding rtnl because scan
and beacon workers acquire it themselves.

Fixes: d021d218f6d9 ("mac802154: Handle received BEACON_REQ")
Signed-off-by: Xuanqiang Luo <redacted>

Missing Cc: stable.

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

Thanks,
Miquèl

Thanks.

I see Sashiko has also found a few new issues, which look valid.
I'll address them as well in the next revision.

pw-bot: cr