Re: [BUG] fs/aio: A possible sleep-in-atomic bug in aio_migratepage

[Al Viro]

On Sat, Oct 07, 2017 at 09:36:48AM +0800, Jia-Ju Bai wrote:
> According to fs/aio.c, cond_resched is called under a spinlock,
> and the function call path is:
> aio_migratepage (acquire the spinlock)
>   migrate_page_copy
>     copy_huge_page
>       __copy_gigantic_page
>         cond_resched
>           might_sleep
> 
> This bug is found by my static analysis tool and my code review.
> A possible fix is to remove cond_resched in __copy_gigantic_page.

How the hell would a huge page end up in page cache of inode created
by aio_private_file()???