Vulnerability Details : CVE-2021-46970
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]
Products affected by CVE-2021-46970
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-46970
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 5 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-46970
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
5.5
|
MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.8
|
3.6
|
NIST | 2025-01-08 |
References for CVE-2021-46970
-
https://git.kernel.org/stable/c/abd1510c08a13c88d24b622a83c82e87ff1d3135
bus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/ed541cff35cbdb695f0c98ef506dd7218883fc07
bus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue - kernel/git/stable/linux.git - Linux kernel stable treePatch
-
https://git.kernel.org/stable/c/0fccbf0a3b690b162f53b13ed8bc442ea33437dc
bus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue - kernel/git/stable/linux.git - Linux kernel stable treePatch
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