Bug 2373671 (CVE-2022-49986)

Summary:	CVE-2022-49986 kernel: scsi: storvsc: Remove WQ_MEM_RECLAIM from storvsc_error_wq
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	dfreiber, drow, jburrell, rhel-process-autobot, vkumar, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-06-18 12:13:14 UTC

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

scsi: storvsc: Remove WQ_MEM_RECLAIM from storvsc_error_wq

storvsc_error_wq workqueue should not be marked as WQ_MEM_RECLAIM as it
doesn't need to make forward progress under memory pressure.  Marking this
workqueue as WQ_MEM_RECLAIM may cause deadlock while flushing a
non-WQ_MEM_RECLAIM workqueue.  In the current state it causes the following
warning:

[   14.506347] ------------[ cut here ]------------
[   14.506354] workqueue: WQ_MEM_RECLAIM storvsc_error_wq_0:storvsc_remove_lun is flushing !WQ_MEM_RECLAIM events_freezable_power_:disk_events_workfn
[   14.506360] WARNING: CPU: 0 PID: 8 at <-snip->kernel/workqueue.c:2623 check_flush_dependency+0xb5/0x130
[   14.506390] CPU: 0 PID: 8 Comm: kworker/u4:0 Not tainted 5.4.0-1086-azure #91~18.04.1-Ubuntu
[   14.506391] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 05/09/2022
[   14.506393] Workqueue: storvsc_error_wq_0 storvsc_remove_lun
[   14.506395] RIP: 0010:check_flush_dependency+0xb5/0x130
		<-snip->
[   14.506408] Call Trace:
[   14.506412]  __flush_work+0xf1/0x1c0
[   14.506414]  __cancel_work_timer+0x12f/0x1b0
[   14.506417]  ? kernfs_put+0xf0/0x190
[   14.506418]  cancel_delayed_work_sync+0x13/0x20
[   14.506420]  disk_block_events+0x78/0x80
[   14.506421]  del_gendisk+0x3d/0x2f0
[   14.506423]  sr_remove+0x28/0x70
[   14.506427]  device_release_driver_internal+0xef/0x1c0
[   14.506428]  device_release_driver+0x12/0x20
[   14.506429]  bus_remove_device+0xe1/0x150
[   14.506431]  device_del+0x167/0x380
[   14.506432]  __scsi_remove_device+0x11d/0x150
[   14.506433]  scsi_remove_device+0x26/0x40
[   14.506434]  storvsc_remove_lun+0x40/0x60
[   14.506436]  process_one_work+0x209/0x400
[   14.506437]  worker_thread+0x34/0x400
[   14.506439]  kthread+0x121/0x140
[   14.506440]  ? process_one_work+0x400/0x400
[   14.506441]  ? kthread_park+0x90/0x90
[   14.506443]  ret_from_fork+0x35/0x40
[   14.506445] ---[ end trace 2d9633159fdc6ee7 ]---

Comment 1 Avinash Hanwate 2025-06-18 18:46:34 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061823-CVE-2022-49986-d434@gregkh/T