From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CEBA2256E for ; Fri, 13 May 2022 23:19:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D4A4C34100; Fri, 13 May 2022 23:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1652483951; bh=nsqqEsbCAJO9Nx/S0guNnQUIdm8rw5xK6VIXgCLIZKM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=UnzcjbtwVrbXBSJ7C2fccqdOzxiXb31wk+hfEkpeaBLXWJdNcx1CpI+LaNUPy6db2 tWzlGaW+UfIm8frhuwsYDs5KRRS0ujdqusYynfLuyf0QIbmMluE0z4ZtrjIfpdzuZz voCrn3e+2upCTSDr9UN5f18p+pJf1Mt8qHCM29u4= Date: Fri, 13 May 2022 16:19:10 -0700 From: Andrew Morton To: Mike Kravetz Cc: syzbot , Minchan Kim , 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 , Stephen Rothwell Subject: Re: [syzbot] WARNING in follow_hugetlb_page Message-Id: <20220513161910.d1b73583cdb2e33562aa86e5@linux-foundation.org> In-Reply-To: References: <000000000000ef451a05dee0f2b1@google.com> <00000000000077377c05dee75f63@google.com> <20220513102617.c464c4f566052838e911a3ec@linux-foundation.org> <75f09063-d184-7d44-17a1-ed04be5eb953@oracle.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 13 May 2022 15:48:15 -0700 Mike Kravetz wrote: > On 5/13/22 11:09, Mike Kravetz wrote: > > On 5/13/22 10:26, Andrew Morton wrote: > >> On Fri, 13 May 2022 09:43:24 -0700 syzbot wrote: > >> > >>> syzbot has found a reproducer for the following issue on: > >> > >> Thanks. > >> > >>> HEAD commit: 1e1b28b936ae Add linux-next specific files for 20220513 > >>> git tree: linux-next > >>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=174ae715f00000 > >>> kernel config: https://syzkaller.appspot.com/x/.config?x=e4eb3c0c4b289571 > >>> dashboard link: https://syzkaller.appspot.com/bug?extid=acf65ca584991f3cc447 > >>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11531766f00000 > >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ce5a9ef00000 > >>> > >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: > >>> Reported-by: syzbot+acf65ca584991f3cc447@syzkaller.appspotmail.com > >>> > >>> ------------[ cut here ]------------ > >>> WARNING: CPU: 1 PID: 3611 at mm/hugetlb.c:6250 follow_hugetlb_page+0x1326/0x1c80 mm/hugetlb.c:6250 > >> > >> The try_grab_folio() added by 822951d84684d ("mm/hugetlb: Use > >> try_grab_folio() instead of try_grab_compound_head()"). That commit > >> has been there over a month so I guess it's something else. Does > >> someone have the time to bisect? > > > > I can recreate in my 'easy to debug' environment, so I can bisect in > > parallel with other things I need to do today. > > > > 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