From 230ac719c500e58e71342be381ad2042a8cffc42 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 8 Sep 2015 15:03:29 -0700 Subject: [PATCH] mm/hwpoison: don't try to unpoison containment-failed pages memory_failure() can be called at any page at any time, which means that we can't eliminate the possibility of containment failure. In such case the best option is to leak the page intentionally (and never touch it later.) We have an unpoison function for testing, and it cannot handle such containment-failed pages, which results in kernel panic (visible with various calltraces.) So this patch suggests that we limit the unpoisonable pages to properly contained pages and ignore any other ones. Testers are recommended to keep in mind that there're un-unpoisonable pages when writing test programs. Signed-off-by: Naoya Horiguchi Tested-by: Wanpeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b0664c23838b..bba2d7c2c9ce 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1445,6 +1445,22 @@ int unpoison_memory(unsigned long pfn) return 0; } + if (page_count(page) > 1) { + pr_info("MCE: Someone grabs the hwpoison page %#lx\n", pfn); + return 0; + } + + if (page_mapped(page)) { + pr_info("MCE: Someone maps the hwpoison page %#lx\n", pfn); + return 0; + } + + if (page_mapping(page)) { + pr_info("MCE: the hwpoison page has non-NULL mapping %#lx\n", + pfn); + return 0; + } + /* * unpoison_memory() can encounter thp only when the thp is being * worked by memory_failure() and the page lock is not held yet.