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From: Minchan Kim <minchan@kernel.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	syzbot <syzbot+acf65ca584991f3cc447@syzkaller.appspotmail.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	llvm@lists.linux.dev, nathan@kernel.org, ndesaulniers@google.com,
	syzkaller-bugs@googlegroups.com, trix@redhat.com,
	Matthew Wilcox <willy@infradead.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	David Hildenbrand <david@redhat.com>
Subject: Re: [syzbot] WARNING in follow_hugetlb_page
Date: Fri, 13 May 2022 17:26:07 -0700	[thread overview]
Message-ID: <Yn73Hz7LkSUv7ycw@google.com> (raw)
In-Reply-To: <4809b134-a37a-50b8-4c25-44548bc1048f@nvidia.com>

On Fri, May 13, 2022 at 05:09:11PM -0700, John Hubbard wrote:
> On 5/13/22 16:54, Minchan Kim wrote:
> > > > I isolated this to Minchan Kim's "mm: fix is_pinnable_page against on cma
> > > > page".  Yes, the fat finger fix is in next-20220513.
> > > > 
> > > > I don't have time to analyze right now, but can confirm that in the
> > > > reproducer is_pinnable_page is returning false after this change when it
> > > > previously returned true.
> > > 
> > > OK, thanks, I dropped mm-fix-is_pinnable_page-against-on-cma-page.patch
> > 
> > Seems like bug of the patch v5 due to change of this
> > 
> >      if (mt & (MIGRATE_CMA | MIGRATE_ISOLATE))
> > 
> > The migration type is not bit type so it shold be
> > 
> > if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
> > 
> 
> Sorry for leading you astray by recommending the bitwise OR, Minchan.
> I overlooked that point even though it was right in front of me.

No worry, John.

Anything else further can we get insight from the warning?

For example, pin_user_pages going on against a hugetlb page
which are concurrently running alloc_contig_range(it's
exported function so anyone can call randomly) so
alloc_contig_range changes pageblock type as MIGRATE_ISOLATE
under us so the hit at the warning?

  reply	other threads:[~2022-05-14  0:26 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-13  9:03 [syzbot] WARNING in follow_hugetlb_page syzbot
2022-05-13 16:43 ` syzbot
2022-05-13 17:26   ` Andrew Morton
2022-05-13 18:09     ` Mike Kravetz
2022-05-13 22:48       ` Mike Kravetz
2022-05-13 23:19         ` Andrew Morton
2022-05-13 23:54           ` Minchan Kim
2022-05-14  0:09             ` John Hubbard
2022-05-14  0:26               ` Minchan Kim [this message]
2022-05-14  0:56                 ` John Hubbard
2022-05-14  1:16                   ` John Hubbard
2022-05-17  3:37                   ` Mike Kravetz
2022-05-18  7:12                     ` John Hubbard
2022-05-20 22:19                     ` Minchan Kim
2022-05-20 22:56                       ` John Hubbard
2022-05-20 23:25                         ` Minchan Kim
2022-05-20 23:31                         ` Mike Kravetz
2022-05-20 23:43                           ` Minchan Kim
2022-05-21  0:04                             ` Mike Kravetz
2022-05-21 15:24                               ` Minchan Kim
2022-05-21 15:51                                 ` David Hildenbrand
2022-05-21 16:36                                   ` Minchan Kim
2022-05-21 16:46                                     ` David Hildenbrand
2022-05-21 18:25                                       ` Minchan Kim
2022-05-21 23:50                                         ` Mike Kravetz
2022-05-14  0:18             ` Andrew Morton

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