Bug 2373560 (CVE-2022-49995)

Summary: CVE-2022-49995 kernel: writeback: avoid use-after-free after removing device
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-06-18 12:08:17 UTC 
In the Linux kernel, the following vulnerability has been resolved:

writeback: avoid use-after-free after removing device

When a disk is removed, bdi_unregister gets called to stop further
writeback and wait for associated delayed work to complete.  However,
wb_inode_writeback_end() may schedule bandwidth estimation dwork after
this has completed, which can result in the timer attempting to access the
just freed bdi_writeback.

Fix this by checking if the bdi_writeback is alive, similar to when
scheduling writeback work.

Since this requires wb->work_lock, and wb_inode_writeback_end() may get
called from interrupt, switch wb->work_lock to an irqsafe lock.
Comment 1 Avinash Hanwate 2025-06-19 12:19:58 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061826-CVE-2022-49995-2d74@gregkh/T
Comment 7 errata-xmlrpc 2025-08-04 01:48:22 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:12525 https://access.redhat.com/errata/RHSA-2025:12525
Comment 8 errata-xmlrpc 2025-08-04 01:58:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:12526 https://access.redhat.com/errata/RHSA-2025:12526