An issue was discovered in the Linux kernel before 5.0.4. 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.
https://support.f5.com/csp/article/K43239141?utm_source=f5support&%3Butm_medium=RSS
https://security.netapp.com/advisory/ntap-20191004-0001/
https://patchwork.kernel.org/patch/10753365/
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.4