From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f174.google.com (mail-ob0-f174.google.com [209.85.214.174]) by kanga.kvack.org (Postfix) with ESMTP id E1C106B009F for ; Fri, 13 Jun 2014 03:12:09 -0400 (EDT) Received: by mail-ob0-f174.google.com with SMTP id va2so2506066obc.33 for ; Fri, 13 Jun 2014 00:12:09 -0700 (PDT) Received: from mail-ob0-f169.google.com (mail-ob0-f169.google.com [209.85.214.169]) by mx.google.com with ESMTPS id q11si4049405oey.29.2014.06.13.00.12.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 13 Jun 2014 00:12:08 -0700 (PDT) Received: by mail-ob0-f169.google.com with SMTP id wp18so2532121obc.28 for ; Fri, 13 Jun 2014 00:12:08 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140612143916.GB8970@arm.com> References: <20140611173851.GA5556@MacBook-Pro.local> <20140612143916.GB8970@arm.com> Date: Fri, 13 Jun 2014 11:12:08 +0400 Message-ID: Subject: Re: kmemleak: Unable to handle kernel paging request From: Denis Kirjanov Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Naoya Horiguchi On 6/12/14, Catalin Marinas wrote: > On Thu, Jun 12, 2014 at 01:00:57PM +0100, Denis Kirjanov wrote: >> On 6/12/14, Denis Kirjanov wrote: >> > On 6/12/14, Catalin Marinas wrote: >> >> On 11 Jun 2014, at 21:04, Denis Kirjanov >> >> wrote: >> >>> On 6/11/14, Catalin Marinas wrote: >> >>>> On Wed, Jun 11, 2014 at 04:13:07PM +0400, Denis Kirjanov wrote: >> >>>>> I got a trace while running 3.15.0-08556-gdfb9454: >> >>>>> >> >>>>> [ 104.534026] Unable to handle kernel paging request for data at >> >>>>> address 0xc00000007f000000 >> >>>> >> >>>> Were there any kmemleak messages prior to this, like "kmemleak >> >>>> disabled"? There could be a race when kmemleak is disabled because >> >>>> of >> >>>> some fatal (for kmemleak) error while the scanning is taking place >> >>>> (which needs some more thinking to fix properly). >> >>> >> >>> No. I checked for the similar problem and didn't find anything >> >>> relevant. >> >>> I'll try to bisect it. >> >> >> >> Does this happen soon after boot? I guess it=E2=80=99s the first scan >> >> (scheduled at around 1min after boot). Something seems to be telling >> >> kmemleak that there is a valid memory block at 0xc00000007f000000. >> > >> > Yeah, it happens after a while with a booted system so that's the >> > first kmemleak scan. >> > >> >> I've bisected to this commit: d4c54919ed86302094c0ca7d48a8cbd4ee753e92 >> "mm: add !pte_present() check on existing hugetlb_entry callbacks". >> Reverting the commit fixes the issue > > I can't figure how this causes the problem but I have more questions. Is > 0xc00000007f000000 address always the same in all crashes? If yes, you > could comment out start_scan_thread() in kmemleak_late_init() to avoid > the scanning thread starting. Once booted, you can run: > > echo dump=3D0xc00000007f000000 > /sys/kernel/debug/kmemleak > > and check the dmesg for what kmemleak knows about that address, when it > was allocated and whether it should be mapped or not. The address is always the same. [ 179.466239] kmemleak: Object 0xc00000007f000000 (size 16777216): [ 179.466503] kmemleak: comm "swapper/0", pid 0, jiffies 4294892300 [ 179.466508] kmemleak: min_count =3D 0 [ 179.466512] kmemleak: count =3D 0 [ 179.466517] kmemleak: flags =3D 0x1 [ 179.466522] kmemleak: checksum =3D 0 [ 179.466526] kmemleak: backtrace: [ 179.466531] [] .memblock_alloc_range_nid+0x68/0x8= 8 [ 179.466544] [] .memblock_alloc_base+0x20/0x58 [ 179.466553] [] .alloc_dart_table+0x5c/0xb0 [ 179.466561] [] .pmac_probe+0x38/0xa0 [ 179.466569] [<000000000002166c>] 0x2166c [ 179.466579] [<0000000000ae0e68>] 0xae0e68 [ 179.466587] [<0000000000009bc4>] 0x9bc4 > -- > Catalin > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org