lkml.org 
[lkml]   [2022]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 02/16] mm/huge_memory: access vm_page_prot with READ_ONCE in remove_migration_pmd
    Date
    vma->vm_page_prot is read lockless from the rmap_walk, it may be updated
    concurrently. Using READ_ONCE to prevent the risk of reading intermediate
    values.

    Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
    ---
    mm/huge_memory.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/mm/huge_memory.c b/mm/huge_memory.c
    index 48ebeb02f7ce..76dc6d003245 100644
    --- a/mm/huge_memory.c
    +++ b/mm/huge_memory.c
    @@ -3304,7 +3304,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)

    entry = pmd_to_swp_entry(*pvmw->pmd);
    get_page(new);
    - pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot));
    + pmde = pmd_mkold(mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)));
    if (pmd_swp_soft_dirty(*pvmw->pmd))
    pmde = pmd_mksoft_dirty(pmde);
    if (is_writable_migration_entry(entry))
    --
    2.23.0
    \
     
     \ /
      Last update: 2022-06-28 15:31    [W:4.754 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site