Bug 2481928 (CVE-2026-46080)
| Summary: | CVE-2026-46080 kernel: ocfs2: split transactions in dio completion to avoid credit exhaustion | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | unspecified | CC: | rhel-process-autobot, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's Oracle Cluster File System 2 (ocfs2) component. During direct I/O (DIO) write operations, specifically in the `ocfs2_dio_end_io_write` function, an issue with transaction splitting can lead to credit exhaustion in the Journaling Block Device 2 (JBD2) subsystem. This can be exploited by a local attacker to cause a denial of service (DoS) by preventing further journaling operations.
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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: | |||
In the Linux kernel, the following vulnerability has been resolved: ocfs2: split transactions in dio completion to avoid credit exhaustion During ocfs2 dio operations, JBD2 may report warnings via following call trace: ocfs2_dio_end_io_write ocfs2_mark_extent_written ocfs2_change_extent_flag ocfs2_split_extent ocfs2_try_to_merge_extent ocfs2_extend_rotate_transaction ocfs2_extend_trans jbd2__journal_restart start_this_handle output: JBD2: kworker/6:2 wants too many credits credits:5450 rsv_credits:0 max:5449 To prevent exceeding the credits limit, modify ocfs2_dio_end_io_write() to handle extents in a batch of transaction. Additionally, relocate ocfs2_del_inode_from_orphan(). The orphan inode should only be removed from the orphan list after the extent tree update is complete. This ensures that if a crash occurs in the middle of extent tree updates, we won't leave stale blocks beyond EOF. This patch also changes the logic for updating the inode size and removing orphan, making it similar to ext4_dio_write_end_io(). Both operations are performed only when everything looks good. Finally, thanks to Jans and Joseph for providing the bug fix prototype and suggestions.