The Linux Kernel versions 4.14, 4.15, and 4.16 has a null pointer dereference which can result in an out of memory (OOM) killing of large mlocked processes. The issue arises from an oom killed process's final thread calling exit_mmap(), which calls munlock_vma_pages_all() for mlocked vmas.This can happen synchronously with the oom reaper's unmap_page_range() since the vma's VM_LOCKED bit is cleared before munlocking (to determine if any other vmas share the memory and are mlocked).
The product dereferences a pointer that it expects to be valid but is NULL.
| Link | Tags |
|---|---|
| https://usn.ubuntu.com/3752-2/ | vendor advisory |
| https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=27ae357fa82be5ab73b2ef8d39dcb8ca2563483a | patch vendor advisory mitigation |
| https://usn.ubuntu.com/3752-3/ | vendor advisory |
| https://access.redhat.com/security/cve/cve-2018-1000200 | third party advisory |
| https://marc.info/?l=linux-kernel&m=152460926619256 | third party advisory mailing list |
| https://access.redhat.com/errata/RHSA-2018:2948 | vendor advisory |
| http://www.securityfocus.com/bid/104397 | vdb entry third party advisory |
| https://marc.info/?l=linux-kernel&m=152400522806945 | third party advisory mailing list |
| https://usn.ubuntu.com/3752-1/ | vendor advisory |
| http://seclists.org/oss-sec/2018/q2/67 | third party advisory mailing list |