ghsa-jfx3-f7mg-7cp3
Vulnerability from github
Published
2024-02-27 21:31
Modified
2024-02-27 21:31
Details

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

bus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue

A recent change created a dedicated workqueue for the state-change work with WQ_HIGHPRI (no strong reason for that) and WQ_MEM_RECLAIM flags, but the state-change work (mhi_pm_st_worker) does not guarantee forward progress under memory pressure, and will even wait on various memory allocations when e.g. creating devices, loading firmware, etc... The work is then not part of a memory reclaim path...

Moreover, this causes a warning in check_flush_dependency() since we end up in code that flushes a non-reclaim workqueue:

[ 40.969601] workqueue: WQ_MEM_RECLAIM mhi_hiprio_wq:mhi_pm_st_worker [mhi] is flushing !WQ_MEM_RECLAIM events_highpri:flush_backlog [ 40.969612] WARNING: CPU: 4 PID: 158 at kernel/workqueue.c:2607 check_flush_dependency+0x11c/0x140 [ 40.969733] Call Trace: [ 40.969740] __flush_work+0x97/0x1d0 [ 40.969745] ? wake_up_process+0x15/0x20 [ 40.969749] ? insert_work+0x70/0x80 [ 40.969750] ? __queue_work+0x14a/0x3e0 [ 40.969753] flush_work+0x10/0x20 [ 40.969756] rollback_registered_many+0x1c9/0x510 [ 40.969759] unregister_netdevice_queue+0x94/0x120 [ 40.969761] unregister_netdev+0x1d/0x30 [ 40.969765] mhi_net_remove+0x1a/0x40 [mhi_net] [ 40.969770] mhi_driver_remove+0x124/0x250 [mhi] [ 40.969776] device_release_driver_internal+0xf0/0x1d0 [ 40.969778] device_release_driver+0x12/0x20 [ 40.969782] bus_remove_device+0xe1/0x150 [ 40.969786] device_del+0x17b/0x3e0 [ 40.969791] mhi_destroy_device+0x9a/0x100 [mhi] [ 40.969796] ? mhi_unmap_single_use_bb+0x50/0x50 [mhi] [ 40.969799] device_for_each_child+0x5e/0xa0 [ 40.969804] mhi_pm_st_worker+0x921/0xf50 [mhi]

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{
  "affected": [],
  "aliases": [
    "CVE-2021-46970"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-27T19:04:07Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue\n\nA recent change created a dedicated workqueue for the state-change work\nwith WQ_HIGHPRI (no strong reason for that) and WQ_MEM_RECLAIM flags,\nbut the state-change work (mhi_pm_st_worker) does not guarantee forward\nprogress under memory pressure, and will even wait on various memory\nallocations when e.g. creating devices, loading firmware, etc... The\nwork is then not part of a memory reclaim path...\n\nMoreover, this causes a warning in check_flush_dependency() since we end\nup in code that flushes a non-reclaim workqueue:\n\n[   40.969601] workqueue: WQ_MEM_RECLAIM mhi_hiprio_wq:mhi_pm_st_worker [mhi] is flushing !WQ_MEM_RECLAIM events_highpri:flush_backlog\n[   40.969612] WARNING: CPU: 4 PID: 158 at kernel/workqueue.c:2607 check_flush_dependency+0x11c/0x140\n[   40.969733] Call Trace:\n[   40.969740]  __flush_work+0x97/0x1d0\n[   40.969745]  ? wake_up_process+0x15/0x20\n[   40.969749]  ? insert_work+0x70/0x80\n[   40.969750]  ? __queue_work+0x14a/0x3e0\n[   40.969753]  flush_work+0x10/0x20\n[   40.969756]  rollback_registered_many+0x1c9/0x510\n[   40.969759]  unregister_netdevice_queue+0x94/0x120\n[   40.969761]  unregister_netdev+0x1d/0x30\n[   40.969765]  mhi_net_remove+0x1a/0x40 [mhi_net]\n[   40.969770]  mhi_driver_remove+0x124/0x250 [mhi]\n[   40.969776]  device_release_driver_internal+0xf0/0x1d0\n[   40.969778]  device_release_driver+0x12/0x20\n[   40.969782]  bus_remove_device+0xe1/0x150\n[   40.969786]  device_del+0x17b/0x3e0\n[   40.969791]  mhi_destroy_device+0x9a/0x100 [mhi]\n[   40.969796]  ? mhi_unmap_single_use_bb+0x50/0x50 [mhi]\n[   40.969799]  device_for_each_child+0x5e/0xa0\n[   40.969804]  mhi_pm_st_worker+0x921/0xf50 [mhi]",
  "id": "GHSA-jfx3-f7mg-7cp3",
  "modified": "2024-02-27T21:31:27Z",
  "published": "2024-02-27T21:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46970"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0fccbf0a3b690b162f53b13ed8bc442ea33437dc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/abd1510c08a13c88d24b622a83c82e87ff1d3135"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed541cff35cbdb695f0c98ef506dd7218883fc07"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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