CVE-2022-49172

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> parisc: Fix non-access data TLB cache flush faults<br /> <br /> When a page is not present, we get non-access data TLB faults from<br /> the fdc and fic instructions in flush_user_dcache_range_asm and<br /> flush_user_icache_range_asm. When these occur, the cache line is<br /> not invalidated and potentially we get memory corruption. The<br /> problem was hidden by the nullification of the flush instructions.<br /> <br /> These faults also affect performance. With pa8800/pa8900 processors,<br /> there will be 32 faults per 4 KB page since the cache line is 128<br /> bytes. There will be more faults with earlier processors.<br /> <br /> The problem is fixed by using flush_cache_pages(). It does the flush<br /> using a tmp alias mapping.<br /> <br /> The flush_cache_pages() call in flush_cache_range() flushed too<br /> large a range.<br /> <br /> V2: Remove unnecessary preempt_disable() and preempt_enable() calls.