From: Naoya Horiguchi Date: Tue, 8 Sep 2015 22:03:29 +0000 (-0700) Subject: mm/hwpoison: don't try to unpoison containment-failed pages X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=230ac719c500e58e71342be381ad2042a8cffc42;p=deliverable%2Flinux.git 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 --- 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.