From 45e55300f11495ed58c53427da7f0d958800a30f Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Thu, 6 Aug 2020 23:23:37 -0700 Subject: mm: remove unnecessary wrapper function do_mmap_pgoff() The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne Signed-off-by: Andrew Morton Reviewed-by: Andrew Morton Reviewed-by: David Hildenbrand Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/hugetlbfs/inode.c') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index ef5313f9c78f..523954d00dff 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -140,7 +140,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) * already been checked by prepare_hugepage_range. If you add * any error returns here, do so after setting VM_HUGETLB, so * is_vm_hugetlb_page tests below unmap_region go the right - * way when do_mmap_pgoff unwinds (may be important on powerpc + * way when do_mmap unwinds (may be important on powerpc * and ia64). */ vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND; -- cgit From 15568299b7d9988063afce60731df605ab236e2a Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Tue, 11 Aug 2020 18:31:35 -0700 Subject: hugetlbfs: prevent filesystem stacking of hugetlbfs syzbot found issues with having hugetlbfs on a union/overlay as reported in [1]. Due to the limitations (no write) and special functionality of hugetlbfs, it does not work well in filesystem stacking. There are no know use cases for hugetlbfs stacking. Rather than making modifications to get hugetlbfs working in such environments, simply prevent stacking. [1] https://lore.kernel.org/linux-mm/000000000000b4684e05a2968ca6@google.com/ Reported-by: syzbot+d6ec23007e951dadf3de@syzkaller.appspotmail.com Suggested-by: Amir Goldstein Signed-off-by: Mike Kravetz Signed-off-by: Andrew Morton Acked-by: Miklos Szeredi Cc: Al Viro Cc: Matthew Wilcox Cc: Colin Walters Link: http://lkml.kernel.org/r/80f869aa-810d-ef6c-8888-b46cee135907@oracle.com Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/hugetlbfs/inode.c') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 523954d00dff..b5c109703daa 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -1364,6 +1364,12 @@ hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_magic = HUGETLBFS_MAGIC; sb->s_op = &hugetlbfs_ops; sb->s_time_gran = 1; + + /* + * Due to the special and limited functionality of hugetlbfs, it does + * not work well as a stacking filesystem. + */ + sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx)); if (!sb->s_root) goto out_free; -- cgit