"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfilemap: replace pte_offset_map() with pte_offset_map_nolock()\n\nThe vmf->ptl in filemap_fault_recheck_pte_none() is still set from\nhandle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte). \nAfter a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table\nmay be racily changed and vmf->ptl maybe fails to protect the actual page\ntable. Fix this by replacing pte_offset_map() with\npte_offset_map_nolock().\n\nAs David said, the PTL pointer might be stale so if we continue to use\nit infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if\nthe PTL fails, the issue fixed by commit 58f327f2ce80 (\"filemap: avoid\nunnecessary major faults in filemap_fault()\") might reappear."