CVE-2026-64438

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

crypto: qat - fix VF2PF work teardown race in adf_disable_sriov()

The VF2PF interrupt handler queues PF-side response work that stores a
raw pointer to per-VF state (struct adf_accel_vf_info). Currently,
adf_disable_sriov() destroys per-VF mutexes and frees vf_info without
stopping new VF2PF work or waiting for in-flight workers to complete. A
concurrently scheduled or already queued worker can then dereference
freed memory.

This manifests as a use-after-free when KASAN is enabled:

  BUG: KASAN: null-ptr-deref in mutex_lock+0x76/0xe0
  Write of size 8 at addr 0000000000000260 by task kworker/24:2/...
  Workqueue: qat_pf2vf_resp_wq adf_iov_send_resp [intel_qat]
  Call Trace:
    kasan_report+0x119/0x140
    mutex_lock+0x76/0xe0
    adf_gen4_pfvf_send+0xd4/0x1f0 [intel_qat]
    adf_recv_and_handle_vf2pf_msg+0x290/0x360 [intel_qat]
    adf_iov_send_resp+0x8c/0xe0 [intel_qat]
    process_one_work+0x6ac/0xfd0
    worker_thread+0x4dd/0xd30
    kthread+0x326/0x410
    ret_from_fork+0x33b/0x670

Add a PF-local flag, vf2pf_disabled, that gates work queueing, worker
processing, and interrupt re-enabling during teardown. Set this flag
atomically with the hardware interrupt mask inside
adf_disable_all_vf2pf_interrupts(). After masking, synchronize the AE
cluster MSI-X interrupt and flush the PF response workqueue before
tearing down per-VF locks and state so all in-flight work completes
before vf_info is destroyed.

Introduce adf_enable_all_vf2pf_interrupts() to clear the flag and
unmask all VF2PF interrupts under the same lock when SR-IOV is
re-enabled. This ensures the software flag and hardware state transition
atomically on both the enable and disable paths.