Re: [PATCH v2 2/2] hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race

From: Kirill A. Shutemov
Date: Fri Dec 21 2018 - 05:28:33 EST


On Tue, Dec 18, 2018 at 02:35:57PM -0800, Mike Kravetz wrote:
> Instead of writing the required complicated code for this rare
> occurrence, just eliminate the race. i_mmap_rwsem is now held in read
> mode for the duration of page fault processing. Hold i_mmap_rwsem
> longer in truncation and hold punch code to cover the call to
> remove_inode_hugepages.

One of remove_inode_hugepages() callers is noticeably missing --
hugetlbfs_evict_inode(). Why?

It at least deserves a comment on why the lock rule doesn't apply to it.

--
Kirill A. Shutemov