Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list). However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 ("pipe_read: don't wake up the writer if the pipe is still full"). p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq). This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.
References
- https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046
- https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a
FAQ
What is CVE-2025-40305?
CVE-2025-40305 is a documented vulnerability. In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if...
How severe is CVE-2025-40305?
CVSS scoring is not yet available for CVE-2025-40305. Check NVD for updates.
Is there a patch for CVE-2025-40305?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.