linux-kernel - Re: [fuse-devel] trying to steal weird page?

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Date:   Thu, 20 Apr 2017 15:29:20 +0200
From:   Miklos Szeredi <miklos@...redi.hu>
To:     Antonio SJ Musumeci <trapexit@...wn.link>
Cc:     fuse-devel <fuse-devel@...ts.sourceforge.net>, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [fuse-devel] trying to steal weird page?

On Wed, Apr 12, 2017 at 11:30:00AM -0400, Antonio SJ Musumeci wrote:
> A user reported getting the below errors when *not* using direct_io
> but atomic_o_trunc, auto_cache, big_writes, default_permissions,
> splice_move, splice_read, and splice_write are enabled.
> 
> Any ideas?

I think this is due to the PageWaiters bit added in v4.10 by

62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit")

That bit is harmless and probably left behind due to a race.  Following patch
should fix the warning.

Thanks,
Miklos

---
 fs/fuse/dev.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -811,6 +811,7 @@ static int fuse_check_page(struct page *
 	       1 << PG_uptodate |
 	       1 << PG_lru |
 	       1 << PG_active |
+	       1 << PG_waiters |
 	       1 << PG_reclaim))) {
 		printk(KERN_WARNING "fuse: trying to steal weird page\n");
 		printk(KERN_WARNING "  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);