On 21/04/08 09:08AM, Miaohe Lin wrote: > Hi all, > When I was investigating the swap code, I found some possible race > windows. This series aims to fix all these races. But using current > get/put_swap_device() to guard against concurrent swapoff for > swap_readpage() looks terrible because swap_readpage() may take really > long time. And to reduce the performance overhead on the hot-path as > much as possible, it appears we can use the percpu_ref to close this > race window(as suggested by Huang, Ying). The patch 1 adds percpu_ref > support for swap and the rest of the patches use this to close various > race windows. More details can be found in the respective changelogs. > Thanks! > > Miaohe Lin (5): > mm/swapfile: add percpu_ref support for swap > swap: fix do_swap_page() race with swapoff > mm/swap_state: fix get_shadow_from_swap_cache() race with swapoff > mm/swap_state: fix potential faulted in race in swap_ra_info() > mm/swap_state: fix swap_cluster_readahead() race with swapoff Somehow I see Patch-1 and Patch-2 are missing on linux-mm[1]. Also I wanted to ask if you have a way to trigger this in a more controlled environment (consistently)? [1]: https://patchwork.kernel.org/project/linux-mm/cover/20210408130820.48233-1-linmiaohe@xxxxxxxxxx/ -ritesh > > include/linux/swap.h | 4 +++- > mm/memory.c | 10 +++++++++ > mm/swap_state.c | 33 +++++++++++++++++++++-------- > mm/swapfile.c | 50 +++++++++++++++++++++++++++----------------- > 4 files changed, 68 insertions(+), 29 deletions(-) > > -- > 2.19.1 > >
