On Tue, 13 Apr 2021 07:43:20 +0900, Naoya Horiguchi wrote: > This patch suggests to do page table walk to find the error virtual > address. If we find multiple virtual addresses in walking, we now can't > determine which one is correct, so we fall back to sending SIGBUS in > kill_me_maybe() without error info as we do now. This corner case needs > to be solved in the future. Instead of walking the page tables, I wonder what about the following idea: When failing to get vaddr, memory_failure just ensures the mapping is removed and an hwpoisoned swap pte is put in place; or the original page is flagged with PG_HWPOISONED and kept in the radix tree (e.g., for SHMEM THP). NOTE: no SIGBUS is sent to user space. Then do_machine_check just returns to user space to resume execution, the re-execution will result in a #PF and should land to the exact page fault handling code that generates a SIGBUS with the precise vaddr info: https://github.com/torvalds/linux/blob/7af08140979a6e7e12b78c93b8625c8d25b084e2/mm/memory.c#L3290 https://github.com/torvalds/linux/blob/7af08140979a6e7e12b78c93b8625c8d25b084e2/mm/memory.c#L3647 Thanks, -Jue
