From: Shaohua Li <shli@xxxxxx> Artem Savkov reported a race condition[1] in MADV_FREE. MADV_FREE clear pte dirty bit and then mark the page lazyfree. There is no lock to prevent the page is added to swap cache between these two steps by page reclaim. There are two problems: - page in swapcache is marked lazyfree (clear SwapBacked). This confuses some code pathes, like page fault handling. - The page is added into swapcache, and freed but the page isn't swapout because pte isn't dity. This will cause data corruption. The patches will fix the issues. Thanks, Shaohua V1->V2: - dirty page in add_to_swap instead of in shrink_page_list as suggested by Minchan Shaohua Li (2): mm: avoid marking swap cached page as lazyfree mm: fix data corruption caused by lazyfree page mm/swap.c | 4 ++-- mm/swap_state.c | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-) -- 2.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
