From: Joseph Salisbury <joseph.salisbury@canonical.com>
To: Thomas Gleixner <tglx@linutronix.de>,
"Yu, Fenghua" <fenghua.yu@intel.com>
Cc: "Shankar, Ravi V" <ravi.v.shankar@intel.com>,
"vikas.shivappa@linux.intel.com" <vikas.shivappa@linux.intel.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Luck, Tony" <tony.luck@intel.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"eranian@google.com" <eranian@google.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"davidcc@google.com" <davidcc@google.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
"1733662@bugs.launchpad.net" <1733662@bugs.launchpad.net>,
"Roderick W. Smith" <rod.smith@canonical.com>
Subject: Re: [REGRESSION][v4.14.y][v4.15] x86/intel_rdt/cqm: Improve limbo list processing
Date: Wed, 17 Jan 2018 15:35:19 -0500 [thread overview]
Message-ID: <7d3e17d9-b7f1-0829-1b2c-83a72deb281b@canonical.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1801161957510.2366@nanos>
On 01/16/2018 01:59 PM, Thomas Gleixner wrote:
> On Tue, 16 Jan 2018, Yu, Fenghua wrote:
>>> From: Thomas Gleixner [mailto:tglx@linutronix.de]
>> Is this a Haswell specific issue?
>>
>> I run the following test forever without issue on Broadwell and 4.15.0-rc6 with rdt mounted:
>> for ((;;)) do
>> for ((i=1;i<88;i++)) do
>> echo 0 >/sys/devices/system/cpu/cpu$i/online
>> done
>> echo "online cpus:"
>> grep processor /proc/cpuinfo |wc
>> for ((i=1;i<88;i++)) do
>> echo 1 >/sys/devices/system/cpu/cpu$i/online
>> done
>> echo "online cpus:"
>> grep processor /proc/cpuinfo|wc
>> done
>>
>> I'm finding a Haswell to reproduce the issue.
> Come on. This is crystal clear from the KASAN trace. And the fix is simple enough.
>
> You simply do not run into it because on your machine
>
> is_llc_occupancy_enabled() is false...
>
> Thanks,
>
> tglx
>
> 8<--------------------
>
> diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
> index 88dcf8479013..99442370de40 100644
> --- a/arch/x86/kernel/cpu/intel_rdt.c
> +++ b/arch/x86/kernel/cpu/intel_rdt.c
> @@ -525,10 +525,6 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
> */
> if (static_branch_unlikely(&rdt_mon_enable_key))
> rmdir_mondata_subdir_allrdtgrp(r, d->id);
> - kfree(d->ctrl_val);
> - kfree(d->rmid_busy_llc);
> - kfree(d->mbm_total);
> - kfree(d->mbm_local);
> list_del(&d->list);
> if (is_mbm_enabled())
> cancel_delayed_work(&d->mbm_over);
> @@ -545,6 +541,10 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
> cancel_delayed_work(&d->cqm_limbo);
> }
>
> + kfree(d->ctrl_val);
> + kfree(d->rmid_busy_llc);
> + kfree(d->mbm_total);
> + kfree(d->mbm_local);
> kfree(d);
> return;
> }
Thanks, Thomas. I'll build some test kernels and have your patch tested
out.
Thanks,
Joe
next prev parent reply other threads:[~2018-01-17 20:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 16:22 [REGRESSION][v4.14.y][v4.15] x86/intel_rdt/cqm: Improve limbo list processing Joseph Salisbury
2018-01-14 11:35 ` Thomas Gleixner
2018-01-16 13:09 ` Thomas Gleixner
[not found] ` <159B72D0-06FE-4925-A11A-1F8A7741BF70@intel.com>
2018-01-16 16:40 ` Joseph Salisbury
2018-01-16 18:09 ` Thomas Gleixner
2018-01-16 18:34 ` Yu, Fenghua
2018-01-16 18:59 ` Thomas Gleixner
2018-01-17 11:00 ` [tip:x86/urgent] x86/intel_rdt/cqm: Prevent use after free tip-bot for Thomas Gleixner
2018-01-17 20:35 ` Joseph Salisbury [this message]
2018-01-17 22:16 ` [REGRESSION][v4.14.y][v4.15] x86/intel_rdt/cqm: Improve limbo list processing Joseph Salisbury
2018-01-17 22:55 ` Thomas Gleixner
2018-01-17 22:59 ` Joseph Salisbury
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