On Mon, 3 Dec 2018 12:08:47 -0800 Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote: > These patches are a follow up to the RFC, > http://lkml.kernel.org/r/20181024045053.1467-1-mike.kravetz@xxxxxxxxxx > Comments made by Naoya were addressed. > > There are two primary issues addressed here: > 1) For shared pmds, huge PE pointers returned by huge_pte_alloc can become > invalid via a call to huge_pmd_unshare by another thread. > 2) hugetlbfs page faults can race with truncation causing invalid global > reserve counts and state. > Both issues are addressed by expanding the use of i_mmap_rwsem. > > These issues have existed for a long time. They can be recreated with a > test program that causes page fault/truncation races. For simple mappings, > this results in a negative HugePages_Rsvd count. If racing with mappings > that contain shared pmds, we can hit "BUG at fs/hugetlbfs/inode.c:444!" or > Oops! as the result of an invalid memory reference. > > I broke up the larger RFC into separate patches addressing each issue. > Hopefully, this is easier to understand/review. Three patches tagged for -stable and no reviewers yet. Could people please take a close look?
