From d3378e86d1822b6d0bebfbc18a8348691c05dfa0 Mon Sep 17 00:00:00 2001 From: Aili Yao Date: Fri, 9 Apr 2021 13:27:19 -0700 Subject: mm/gup: check page posion status for coredump. When we do coredump for user process signal, this may be an SIGBUS signal with BUS_MCEERR_AR or BUS_MCEERR_AO code, which means this signal is resulted from ECC memory fail like SRAR or SRAO, we expect the memory recovery work is finished correctly, then the get_dump_page() will not return the error page as its process pte is set invalid by memory_failure(). But memory_failure() may fail, and the process's related pte may not be correctly set invalid, for current code, we will return the poison page, get it dumped, and then lead to system panic as its in kernel code. So check the poison status in get_dump_page(), and if TRUE, return NULL. There maybe other scenario that is also better to check the posion status and not to panic, so make a wrapper for this check, Thanks to David's suggestion(). [akpm@linux-foundation.org: s/0/false/] [yaoaili@kingsoft.com: is_page_poisoned() arg cannot be null, per Matthew] Link: https://lkml.kernel.org/r/20210322115233.05e4e82a@alex-virtual-machine Link: https://lkml.kernel.org/r/20210319104437.6f30e80d@alex-virtual-machine Signed-off-by: Aili Yao Cc: David Hildenbrand Cc: Matthew Wilcox Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Mike Kravetz Cc: Aili Yao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'mm/gup.c') diff --git a/mm/gup.c b/mm/gup.c index e40579624f10..ef7d2da9f03f 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1535,6 +1535,10 @@ struct page *get_dump_page(unsigned long addr) FOLL_FORCE | FOLL_DUMP | FOLL_GET); if (locked) mmap_read_unlock(mm); + + if (ret == 1 && is_page_poisoned(page)) + return NULL; + return (ret == 1) ? page : NULL; } #endif /* CONFIG_ELF_CORE */ -- cgit v1.2.1