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 processs final thread calling exit_mmap(), which calls munlock_vma_pages_all() for mlocked vmas.This can happen synchronously with the oom reapers unmap_page_range() since the vmas VM_LOCKED bit is cleared before munlocking (to determine if any other vmas share the memory and are mlocked).
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Linux_kernel | Linux | 4.14 (including) | 4.14 (including) |
| Linux_kernel | Linux | 4.15 (including) | 4.15 (including) |
| Linux_kernel | Linux | 4.16 (including) | 4.16 (including) |