Bug 2536781 (CVE-2026-90420)

Summary:	CVE-2026-90420 kernel: nilfs2: fix infinite loop in nilfs_clean_segments()
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:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in the nilfs2 component of the Linux kernel. When the nilfs2 filesystem encounters an I/O error and is subsequently remounted as read-only, a cleaner input/output control (ioctl) operation can enter an infinite loop. This condition causes the affected task to hang indefinitely, leading to a Denial of Service (DoS) for the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 19:33:04 UTC

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

nilfs2: fix infinite loop in nilfs_clean_segments()

syzbot reported a hung task in nilfs_transaction_begin(). This occurs
because the cleaner ioctl falls into an infinite loop if
nilfs_segctor_construct() repeatedly returns -EROFS (e.g. the device
is remounted as read-only after an I/O error).

Currently in nilfs_clean_segments(), if err is non-zero, it logs the
error and sleeps but doesn't abort when it encounters a terminal error
like -EROFS. This causes the thread to loop forever.

Fix this by breaking out of the loop if nilfs_segctor_construct()
returns -EROFS. This matches the behaviour in
nilfs_segctor_write_out(), which also handles -EROFS.

Comment 1 gkamathe 2026-09-21 12:55:49 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90420.mbox