CVE-2021-46970

2024-02-2719:04:07

416baaa9-dc9f-4396-8d5f-8c081fb06d67

web.nvd.nist.gov

2479

cve-2021-46970

linux kernel

vulnerability

mhi_pm_st_worker

wq_mem_reclaim

security fix

6.7 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.7%

JSON

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]

Affected configurations

Vulners

Node

linuxlinux_kernelRange5.11–5.11.20

linuxlinux_kernelRange5.12.0–5.12.3

linuxlinux_kernelRange5.13.0≥

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/bus/mhi/core/init.c"
    ],
    "versions": [
      {
        "version": "8f7039787687",
        "lessThan": "abd1510c08a1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "8f7039787687",
        "lessThan": "ed541cff35cb",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "8f7039787687",
        "lessThan": "0fccbf0a3b69",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/bus/mhi/core/init.c"
    ],
    "versions": [
      {
        "version": "5.11",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.11",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.11.20",
        "lessThanOrEqual": "5.11.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.12.3",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]