From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Borislav Petkov <bp@amd64.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Jan Kara <jack@suse.cz>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <jweiner@redhat.com>,
Conny Seidel <conny.seidel@amd.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: divide error: bdi_dirty_limit+0x5a/0x9e
Date: Mon, 24 Sep 2012 17:21:29 +0530 [thread overview]
Message-ID: <50604941.9050806@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120924113447.GA25182@localhost>
On 09/24/2012 05:04 PM, Fengguang Wu wrote:
> On Mon, Sep 24, 2012 at 04:43:11PM +0530, Srivatsa S. Bhat wrote:
>> On 09/24/2012 04:35 PM, Borislav Petkov wrote:
>>> On Mon, Sep 24, 2012 at 04:08:33PM +0530, Srivatsa S. Bhat wrote:
>>>> On 09/24/2012 03:53 PM, Borislav Petkov wrote:
>>>>> Hi all,
>>>>>
>>>>> we're able to trigger the oops below when doing CPU hotplug tests.
>>>>>
>>>>
>>>> I hit this problem as well, which I reported here, a few days ago:
>>>> https://lkml.org/lkml/2012/9/13/222
>>>
>>> Ok, your case shows even more info:
>>>
>>> [ 526.024180] divide error: 0000 [#1] SMP
>>> [ 526.028144] Modules linked in: ipv6 cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf fuse loop dm_mod iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm cdc_ether pcspkr usbnet shpchp pci_hotplug i2c_i801 i2c_core ioatdma mii crc32c_intel serio_raw microcode lpc_ich mfd_core i7core_edac bnx2 dca edac_core tpm_tis tpm sg tpm_bios rtc_cmos button uhci_hcd ehci_hcd usbcore usb_common sd_mod crc_t10dif edd ext3 mbcache jbd fan processor mptsas mptscsih mptbase scsi_transport_sas scsi_mod thermal thermal_sys hwmon
>>> [ 526.028145] CPU 9
>>> [ 526.028145] Pid: 2235, comm: flush-8:0 Not tainted 3.6.0-rc1-tglx-hotplug-0.0.0.28.36b5ec9-default #1 IBM IBM System x -[7870C4Q]-/68Y8033
>>> [ 526.028145] RIP: 0010:[<ffffffff811276f6>] [<ffffffff811276f6>] bdi_dirty_limit+0x66/0xc0
>>> [ 526.028145] RSP: 0018:ffff8811530bfcc0 EFLAGS: 00010206
>>> [ 526.028145] RAX: 0000000000b9877e RBX: 00000000001a8112 RCX: 28f5c28f5c28f5c3
>>> [ 526.028145] RDX: 0000000000000000 RSI: 0000000000b9877e RDI: 0000000000000000
>>>
>>> %rax contains something != 0 but %rdi definitely is 0.
>>>
>>
>> Yep.. So I tried putting a BUG_ON(!den) in fprop_fraction_percpu() to
>> catch if we really got the code wrong somehow.. but unfortunately, with
>> that added, I haven't been successful in reproducing the bug :(
>
> Will you test such a line? At least the generic do_div() only uses the
> lower 32bits for division.
>
> WARN_ON(!(den & 0xffffffff));
>
Sure, I'll test this and report back. Thanks for the suggestion!
Regards,
Srivatsa S. Bhat
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next prev parent reply other threads:[~2012-09-24 11:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-24 10:23 divide error: bdi_dirty_limit+0x5a/0x9e Borislav Petkov
2012-09-24 10:38 ` Srivatsa S. Bhat
2012-09-24 11:05 ` Borislav Petkov
2012-09-24 11:13 ` Srivatsa S. Bhat
2012-09-24 11:34 ` Fengguang Wu
2012-09-24 11:51 ` Srivatsa S. Bhat [this message]
2012-09-24 12:20 ` Borislav Petkov
2012-09-24 12:29 ` Fengguang Wu
2012-09-24 12:56 ` Borislav Petkov
2012-09-24 18:54 ` Srivatsa S. Bhat
2012-09-24 14:23 ` Jan Kara
2012-09-24 14:36 ` Borislav Petkov
2012-09-24 18:16 ` Conny Seidel
2012-09-24 18:19 ` Borislav Petkov
2012-09-24 18:48 ` Srivatsa S. Bhat
2012-09-24 19:31 ` Borislav Petkov
2012-09-24 20:07 ` Jan Kara
2012-09-24 20:17 ` Jan Kara
2012-09-24 21:21 ` Andrew Morton
2012-09-24 22:27 ` Jan Kara
2012-09-25 8:57 ` Conny Seidel
2012-09-24 20:48 ` [PATCH] CPU hotplug, writeback: Don't call writeback_set_ratelimit() too often during hotplug Srivatsa S. Bhat
2012-09-28 12:27 ` Fengguang Wu
2012-09-28 14:46 ` Srivatsa S. Bhat
2012-10-03 23:11 ` Ni zhan Chen
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