CVE-2022-50446

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ARC: mm: fix leakage of memory allocated for PTE<br /> <br /> Since commit d9820ff ("ARC: mm: switch pgtable_t back to struct page *")<br /> a memory leakage problem occurs. Memory allocated for page table entries<br /> not released during process termination. This issue can be reproduced by<br /> a small program that allocates a large amount of memory. After several<br /> runs, you&amp;#39;ll see that the amount of free memory has reduced and will<br /> continue to reduce after each run. All ARC CPUs are effected by this<br /> issue. The issue was introduced since the kernel stable release v5.15-rc1.<br /> <br /> As described in commit d9820ff after switch pgtable_t back to struct<br /> page *, a pointer to "struct page" and appropriate functions are used to<br /> allocate and free a memory page for PTEs, but the pmd_pgtable macro hasn&amp;#39;t<br /> changed and returns the direct virtual address from the PMD (PGD) entry.<br /> Than this address used as a parameter in the __pte_free() and as a result<br /> this function couldn&amp;#39;t release memory page allocated for PTEs.<br /> <br /> Fix this issue by changing the pmd_pgtable macro and returning pointer to<br /> struct page.