CVE-2025-68771: ocfs2: fix kernel BUG in ocfs2_find_victim_chain
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix kernel BUG in ocfs2findvictimchain
syzbot reported a kernel BUG in ocfs2findvictimchain() because the clnextfreerec field of the allocation chain list (next free slot in the chain list) is 0, triggring the BUGON(!cl->clnextfreerec) condition in ocfs2findvictimchain() and panicking the kernel.
To fix this, an if condition is introduced in ocfs2claimsuballocbits(), just before calling ocfs2findvictimchain(), the code block in it being executed when either of the following conditions is true:
1. clnextfreerec is equal to 0, indicating that there are no free chains in the allocation chain list 2. clnextfreerec is greater than clcount (the total number of chains in the allocation chain list)
Either of them being true is indicative of the fact that there are no chains left for usage.
This is addressed using ocfs2error(), which prints the error log for debugging purposes, rather than panicking the kernel.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.13-1
Event History
Frequently Asked Questions
What is the severity of CVE-2025-68771?
CVE-2025-68771 has been classified with a medium severity that may cause a kernel BUG in the ocfs2_find_victim_chain function.
How do I fix CVE-2025-68771?
To fix CVE-2025-68771, update your Linux kernel to the latest version where the vulnerability has been patched.
What systems are affected by CVE-2025-68771?
CVE-2025-68771 affects the ocfs2 filesystem within the Linux kernel.
What are the potential impacts of CVE-2025-68771?
The potential impact of CVE-2025-68771 includes system instability and possible denial of service conditions due to the kernel BUG.
Who is responsible for addressing CVE-2025-68771?
System administrators and maintainers of affected Linux kernel installations are responsible for addressing CVE-2025-68771 by applying the necessary updates.