From: Catalin Marinas <catalin.marinas@arm.com>
To: Denis Kirjanov <kda@linux-powerpc.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: kmemleak: Unable to handle kernel paging request
Date: Thu, 12 Jun 2014 15:39:16 +0100 [thread overview]
Message-ID: <20140612143916.GB8970@arm.com> (raw)
In-Reply-To: <CAOJe8K2WaJUP9_buwgKw89fxGe56mGP1Mn8rDUO9W48KZzmybA@mail.gmail.com>
On Thu, Jun 12, 2014 at 01:00:57PM +0100, Denis Kirjanov wrote:
> On 6/12/14, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> > On 6/12/14, Catalin Marinas <catalin.marinas@arm.com> wrote:
> >> On 11 Jun 2014, at 21:04, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> >>> On 6/11/14, Catalin Marinas <catalin.marinas@arm.com> 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’s 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=0xc00000007f000000 > /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.
--
Catalin
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Denis Kirjanov <kda@linux-powerpc.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: kmemleak: Unable to handle kernel paging request
Date: Thu, 12 Jun 2014 15:39:16 +0100 [thread overview]
Message-ID: <20140612143916.GB8970@arm.com> (raw)
In-Reply-To: <CAOJe8K2WaJUP9_buwgKw89fxGe56mGP1Mn8rDUO9W48KZzmybA@mail.gmail.com>
On Thu, Jun 12, 2014 at 01:00:57PM +0100, Denis Kirjanov wrote:
> On 6/12/14, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> > On 6/12/14, Catalin Marinas <catalin.marinas@arm.com> wrote:
> >> On 11 Jun 2014, at 21:04, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> >>> On 6/11/14, Catalin Marinas <catalin.marinas@arm.com> 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 ita??s 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=0xc00000007f000000 > /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.
--
Catalin
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next prev parent reply other threads:[~2014-06-12 14:39 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-11 12:13 kmemleak: Unable to handle kernel paging request Denis Kirjanov
2014-06-11 12:13 ` Denis Kirjanov
2014-06-11 17:38 ` Catalin Marinas
2014-06-11 17:38 ` Catalin Marinas
2014-06-11 20:04 ` Denis Kirjanov
2014-06-11 20:04 ` Denis Kirjanov
2014-06-11 22:00 ` Catalin Marinas
2014-06-11 22:00 ` Catalin Marinas
2014-06-12 7:39 ` Denis Kirjanov
2014-06-12 7:39 ` Denis Kirjanov
2014-06-12 12:00 ` Denis Kirjanov
2014-06-12 12:00 ` Denis Kirjanov
2014-06-12 13:29 ` Naoya Horiguchi
2014-06-12 14:39 ` Catalin Marinas [this message]
2014-06-12 14:39 ` Catalin Marinas
2014-06-13 7:12 ` Denis Kirjanov
2014-06-13 7:12 ` Denis Kirjanov
2014-06-13 8:56 ` Catalin Marinas
2014-06-13 8:56 ` Catalin Marinas
2014-06-13 8:56 ` Catalin Marinas
2014-06-13 10:26 ` Denis Kirjanov
2014-06-13 10:26 ` Denis Kirjanov
2014-06-13 10:26 ` Denis Kirjanov
2014-06-16 2:40 ` Michael Ellerman
2014-06-16 2:40 ` Michael Ellerman
2014-06-13 21:44 ` Benjamin Herrenschmidt
2014-06-13 21:44 ` Benjamin Herrenschmidt
2014-06-14 12:05 ` Catalin Marinas
2014-06-14 12:05 ` Catalin Marinas
2014-06-14 12:05 ` Catalin Marinas
[not found] ` <5399ab3b.4825e00a.60fd.5014SMTPIN_ADDED_BROKEN@mx.google.com>
2014-06-13 6:39 ` Denis Kirjanov
2014-06-13 6:39 ` Denis Kirjanov
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