CVE ID:	CVE-2020-25221
Description:	get_gate_page in mm/gup.c in the Linux kernel 5.7.x and 5.8.x before 5.8.7 allows privilege escalation because of incorrect reference counting (caused by gate page mishandling) of the struct page that backs the vsyscall page. The result is a refcount underflow. This can be triggered by any 64-bit process that can use ptrace() or process_vm_readv(), aka CID-9fa2dd946743.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2020-25221 https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8.7 https://git.kernel.org/linus/8891adc61dce2a8a41fc0c23262b681c3ec4b73a https://git.kernel.org/linus/9fa2dd946743ae6f30dc4830da19147bf100a7f2 https://www.openwall.com/lists/oss-security/2020/09/08/4 http://www.openwall.com/lists/oss-security/2020/09/10/4