Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain;
        charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\))
Subject: Re: [PATCH v2 1/2] optee: fix tee out of memory failure seen during
 kexec reboot
From:   Allen Pais <apais@linux.microsoft.com>
In-Reply-To: <CAHUa44FyGOj5=Z80km_2T-avKiJpGVD8cWjTC3ZCX8csazP3rw@mail.gmail.com>
Date:   Wed, 5 May 2021 19:15:23 +0530
Cc:     Allen Pais <allen.lkml@gmail.com>, zajec5@gmail.com,
        bcm-kernel-feedback-list@broadcom.com,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        OP-TEE TrustedFirmware <op-tee@lists.trustedfirmware.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <409F60D9-F0FB-4B69-B64B-CC6B3704038E@linux.microsoft.com>
References: <20210225090610.242623-1-allen.lkml@gmail.com>
 <20210225090610.242623-2-allen.lkml@gmail.com>
 <CAHUa44F5Ew6U80t7PPmV1J4KunXBm_izBxVrxg=x8azjBz0r9Q@mail.gmail.com>
 <9a6c017c-d156-f939-f907-d6dfe83c41ac@linux.microsoft.com>
 <CAHUa44FyGOj5=Z80km_2T-avKiJpGVD8cWjTC3ZCX8csazP3rw@mail.gmail.com>
To:     Jens Wiklander <jens.wiklander@linaro.org>
Precedence: bulk

Jens,=20

>>>> [    0.368428] tee_bnxt_fw optee-clnt0: tee_shm_alloc failed
>>>> [    0.368461] tee_bnxt_fw: probe of optee-clnt0 failed with error =
-22
>>>>=20
>>>> tee_shm_release() is not invoked on dma shm buffer.
>>>>=20
>>>> Implement .shutdown() method to handle the release of the buffers
>>>> correctly.
>>>>=20
>>>> More info:
>>>> https://github.com/OP-TEE/optee_os/issues/3637
>>>>=20
>>>> Signed-off-by: Allen Pais <apais@linux.microsoft.com>
>>>> ---
>>>>  drivers/tee/optee/core.c | 20 ++++++++++++++++++++
>>>>  1 file changed, 20 insertions(+)
>>>=20
>>> This looks good to me. Do you have a practical way of testing this =
on
>>> QEMU for instance?
>>>=20
>>=20
>> Jens,
>>=20
>>   I could not reproduce nor create a setup using QEMU, I could only
>> do it on a real h/w.
>>=20
>>   I have extensively tested the fix and I don't see any issues.
>=20
> I did a few test runs too, seems OK.

 I carried these changes and have not run into any issues with Kexec so =
far.
Last week, while trying out kdump, we ran into a crash(this is when the
Kdump kernel reboots).

$echo c > /proc/sysrq-trigger

Leads to:

[   18.004831] Unable to handle kernel paging request at virtual address =
ffff0008dcef6758
[   18.013002] Mem abort info:
[   18.015885]   ESR =3D 0x96000005
[   18.019034]   EC =3D 0x25: DABT (current EL), IL =3D 32 bits
[   18.024516]   SET =3D 0, FnV =3D 0
[   18.027667]   EA =3D 0, S1PTW =3D 0
[   18.030905] Data abort info:
[   18.033877]   ISV =3D 0, ISS =3D 0x00000005
[   18.037835]   CM =3D 0, WnR =3D 0
[   18.040896] swapper pgtable: 4k pages, 48-bit VAs, =
pgdp=3D0000000970a78000
[   18.047811] [ffff0008dcef6758] pgd=3D000000097fbf9003, =
pud=3D0000000000000000
[   18.054819] Internal error: Oops: 96000005 [#1] SMP
[   18.059850] Modules linked in: bnxt_en pcie_iproc_platform pcie_iproc =
diagbe(O)
[   18.067395] CPU: 3 PID: 1 Comm: systemd-shutdow Tainted: G           =
O      5.4.83-microsoft-standard #1
[   18.077174] Hardware name: Overlake (DT)
[   18.081219] pstate: 80400005 (Nzcv daif +PAN -UAO)
[   18.086170] pc : tee_shm_free+0x18/0x48
[   18.090126] lr : optee_disable_shm_cache+0xa4/0xf0
[   18.095066] sp : ffff80001005bb90
[   18.098484] x29: ffff80001005bb90 x28: ffff000037e20000=20
[   18.103962] x27: 0000000000000000 x26: ffff00003ed10490=20
[   18.109440] x25: ffffca760e975f90 x24: 0000000000000000=20
[   18.114918] x23: ffffca760ed79808 x22: ffff00003ec66e18=20
[   18.120396] x21: ffff80001005bc08 x20: 00000000b200000a=20
[   18.125874] x19: ffff0008dcef6700 x18: 0000000000000010=20
[   18.131352] x17: 0000000000000000 x16: 0000000000000000=20
[   18.136829] x15: ffffffffffffffff x14: ffffca760ed79808=20
[   18.142307] x13: ffff80009005b897 x12: ffff80001005b89f=20
[   18.147786] x11: ffffca760eda4000 x10: ffff80001005b820=20
[   18.153264] x9 : 00000000ffffffd0 x8 : ffffca760e59b2c0=20
[   18.158742] x7 : 0000000000000000 x6 : 0000000000000000=20
[   18.164220] x5 : 0000000000000000 x4 : 0000000000000000=20
[   18.169698] x3 : 0000000000000000 x2 : ffff0008dcef6700=20
[   18.175175] x1 : 00000000ffff0008 x0 : ffffca760e59ca04=20
[   18.180654] Call trace:
[   18.183176]  tee_shm_free+0x18/0x48
[   18.186773]  optee_disable_shm_cache+0xa4/0xf0
[   18.191356]  optee_shutdown+0x20/0x30
[   18.195135]  platform_drv_shutdown+0x2c/0x38
[   18.199538]  device_shutdown+0x180/0x298
[   18.203586]  kernel_restart_prepare+0x44/0x50
[   18.208078]  kernel_restart+0x20/0x68
[   18.211853]  __do_sys_reboot+0x104/0x258
[   18.215899]  __arm64_sys_reboot+0x2c/0x38
[   18.220035]  el0_svc_handler+0x90/0x138
[   18.223991]  el0_svc+0x8/0x208
[   18.227143] Code: f9000bf3 aa0003f3 aa1e03e0 d503201f (b9405a60)=20
[   18.233435] ---[ end trace 835d756cd66aa959 ]---
[   18.238621] Kernel panic - not syncing: Fatal exception
[   18.244014] Kernel Offset: 0x4a75fde00000 from 0xffff800010000000
[   18.250299] PHYS_OFFSET: 0xffff99c680000000
[   18.254613] CPU features: 0x0002,21806008
[   18.258747] Memory Limit: none
[   18.262310] ---[ end Kernel panic - not syncing: Fatal exception ]=E2=80=
=94

I see that before secure world returns OPTEE_SMC_RETURN_ENOTAVAIL(which
Should disable and clear all the cache) we run into the crash trying to =
free shm.

Thoughts?

Thanks.=