[BUG] drivers/bluetooth: use-after-free

[co]

We found a bug reachable in:

    path    drivers/bluetooth
    crash   use-after-free
    commit  7cbfb180945c ("net/sched: sch_cake: fix autorate reconfiguration throttling")

Config, environment, the sanitizer report and a C reproducer follow.

== Notes ===============================================================
    If you patch the bug based on our artifacts, a tag would be
    appreciated:

Reported-by: co+ef32d1251d8555af@xxxxxxx

    Everything in this mail is validated by the reproducer below.

    We also hold an LLM-generated root-cause analysis and a candidate
    patch. The patch passes an A/B test: the same reproducer panics the
    unpatched kernel and runs clean on the patched one. Neither has had
    human review, so both still require validation before you send or
    apply them. Available on:

        patch.diff  https://bugs.sh/b/ef32d1251d8555af/patch.diff
        report.md   https://bugs.sh/b/ef32d1251d8555af/report.md

    This is an open science project. The code and the full set of PoCs
    are not public at this moment, as we intend to disclose our findings
    in an ethical way.

    Happy to test patches. Complaints and suggestions about our work
    are welcome at:

        cedalion@xxxxxxx

== Environment =========================================================
    Reproduced on  7cbfb180945c ("net/sched: sch_cake: fix autorate reconfiguration throttling")
    VM setup       https://bugs.sh/b/ef32d1251d8555af/run.sh
    config         https://bugs.sh/b/ef32d1251d8555af/config.gz
    poc            https://bugs.sh/b/ef32d1251d8555af/repro.c

== Sanitizer Report ====================================================
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:155 (discriminator 1) kernel/locking/spinlock.c:181 (discriminator 1))
Read of size 1 at addr ffff88802ae9c1a8 by task kworker/0:0/9
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 7.2.0-07243-gf87cd64fed58 #63 PREEMPT(full)
Workqueue: events btusb_rx_work
Call Trace:
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
__kasan_check_byte (mm/kasan/common.c:574)
lock_acquire (include/linux/kasan.h:402 (discriminator 1) kernel/locking/lockdep.c:5860 (discriminator 1) kernel/locking/lockdep.c:5843 (discriminator 1))
_raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:155 (discriminator 1) kernel/locking/spinlock.c:181 (discriminator 1))
skb_dequeue (net/core/skbuff.c:3987 (discriminator 1))
btusb_rx_work (drivers/bluetooth/btusb.c:2519)
process_one_work (kernel/workqueue.c:3322)
worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
Allocated by task 793:
Freed by task 1234:
Last potentially related work creation:
The buggy address belongs to the object at ffff88802ae9c000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 424 bytes inside of


---
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This report is generated by a bot. It may contain errors.
See https://github.com/n132/cedalion for more information.

For any issue with this report, reach out to cedalion@xxxxxxx

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