From 6b970599e807ea95c653926d41b095a92fd381e2 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Fri, 9 Dec 2022 15:28:01 +0800 Subject: mm: hwpoison: support recovery from ksm_might_need_to_copy() When the kernel copies a page from ksm_might_need_to_copy(), but runs into an uncorrectable error, it will crash since poisoned page is consumed by kernel, this is similar to the issue recently fixed by Copy-on-write poison recovery. When an error is detected during the page copy, return VM_FAULT_HWPOISON in do_swap_page(), and install a hwpoison entry in unuse_pte() when swapoff, which help us to avoid system crash. Note, memory failure on a KSM page will be skipped, but still call memory_failure_queue() to be consistent with general memory failure process, and we could support KSM page recovery in the feature. [wangkefeng.wang@huawei.com: enhance unuse_pte(), fix issue found by lkp] Link: https://lkml.kernel.org/r/20221213120523.141588-1-wangkefeng.wang@huawei.com [wangkefeng.wang@huawei.com: update changelog, alter ksm_might_need_to_copy(), restore unlikely() in unuse_pte()] Link: https://lkml.kernel.org/r/20230201074433.96641-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20221209072801.193221-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Naoya Horiguchi Cc: Miaohe Lin Cc: Tony Luck Signed-off-by: Andrew Morton --- mm/memory.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 3e836fecd035..f526b9152bef 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3840,6 +3840,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (unlikely(!page)) { ret = VM_FAULT_OOM; goto out_page; + } else if (unlikely(PTR_ERR(page) == -EHWPOISON)) { + ret = VM_FAULT_HWPOISON; + goto out_page; } folio = page_folio(page); -- cgit v1.2.3