linux-kernel - Re: WARNING: CPU: 1 PID: 83 at arch/x86/kernel/cpu/sgx/main.c:446 ksgxd+0x1b7/0x1d0

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Message-ID: <54818a03-93c0-8039-b847-d030785e725a@molgen.mpg.de>
Date:   Thu, 25 Aug 2022 08:46:19 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Jarkko Sakkinen <jarkko@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "Chatre, Reinette" <reinette.chatre@...el.com>,
        linux-sgx@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: WARNING: CPU: 1 PID: 83 at arch/x86/kernel/cpu/sgx/main.c:446
 ksgxd+0x1b7/0x1d0

Dear Jarkko,


Am 25.08.22 um 07:25 schrieb Jarkko Sakkinen:
> On Thu, Aug 25, 2022 at 07:57:30AM +0300, Jarkko Sakkinen wrote:
>> On Fri, Aug 19, 2022 at 11:28:24AM -0700, Dave Hansen wrote:
>>> On 8/19/22 09:02, Paul Menzel wrote:
>>>> On the Dell XPS 13 9370, Linux 5.18.16 prints the warning below:
>>>>
>>>> ```
>>>> [    0.000000] Linux version 5.18.0-4-amd64 (debian-kernel@...ts.debian.org) (gcc-11 (Debian 11.3.0-5) 11.3.0, GNU ld (GNU Binutils for Debian) 2.38.90.20220713) #1 SMP PREEMPT_DYNAMIC Debian 5.18.16-1 (2022-08-10)
>>>> [    0.000000] Command line: BOOT_IMAGE=/vmlinuz-5.18.0-4-amd64 root=UUID=56f398e0-1e25-4fda-aa9f-611dece4b333 ro quiet
>>>> […]
>>>> [    0.000000] DMI: Dell Inc. XPS 13 9370/0RMYH9, BIOS 1.21.0 07/06/2022
>>>> […]
>>>> [    0.235418] sgx: EPC section 0x40200000-0x45f7ffff

>>> Would you be able to send the entire dmesg, along with:
>>>
>>> 	cat /proc/iomem # (as root)
>>> and
>>> 	cpuid -1 --raw
>>>
>>> I'm suspecting either a BIOS problem.  Reinette (cc'd) also thought this
>>> might be a case of the SGX initialization getting a bit too far along
>>> when it should have been disabled.
>>>
>>> We had some bugs where we didn't stop fast enough after spitting out the
>>> "SGX Launch Control is locked..." errors.
>>
>> For some reason the pages do not get properly sanitized:
>>
>> 	/* sanity check: */
>> 	WARN_ON(!list_empty(&sgx_dirty_page_list));
>>
>> EPC should be good, given that EREMOVE does not fail.
>> If SGX would be disabled, also EREMOVE should fail.
> 
> Sorry forgot that in no circumstances we're printing the
> error code inside __sgx_sanitize_pages(). I wrote a quick
> patch to address this (attached) [*].
> 
> Paul,
> 
> Any chance to try the patch out?

Yes, I am going to try it in the next days.

> It's pretty hard to attach e.g. kprobe to grab this info. Does it
> reproduce every single time?
Yes, on each boot up.

> Alternatively: what kind of workload is triggering this?
> I do own 2020 model XPS13, which might be able to
> reproduce the same issue.

The Dell XPS 13 9370 is from 2018 (Intel i5-8350U), so no idea if it 
happens with later processors.


Kind regards,

Paul


> [*] Also: https://lore.kernel.org/linux-sgx/20220825051827.246698-1-jarkko@kernel.org/T/#u