An issue was discovered in the Linux kernel. The 9p filesystem did not protect i_size_write() properly, which causes an i_size_read() infinite loop and denial of service on SMP systems. Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5e3cc1ee1405a7eb3487ed24f786dec01b4cbe1f References: https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.4 https://patchwork.kernel.org/patch/10753365/
Mitigation: As the 9p module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions: # echo "install 9p /bin/true" >> /etc/modprobe.d/disable-9p.conf The system will need to be restarted if the 9p modules are loaded. In most circumstances, the 9p kernel modules will be unable to be unloaded while the filesystems are in use. If the system requires this module to work correctly, this mitigation may not be suitable. If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services.
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2019-16413