Re: [PATCH v14 00/39] arm64/sme: Initial support for the Scalable Matrix Extension

From: Naresh Kamboju <naresh.kamboju@linaro.org>
To: Mark Brown <broonie@kernel.org>
Cc: Qian Cai <quic_qiancai@quicinc.com>,
	Marc Zyngier <maz@kernel.org>,
	 Basant Kumar Dwivedi <Basant.KumarDwivedi@arm.com>,
	Will Deacon <will@kernel.org>,
	 Luis Machado <luis.machado@arm.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	 Catalin Marinas <catalin.marinas@arm.com>,
	Alan Hayward <alan.hayward@arm.com>,
	Salil Akerkar <Salil.Akerkar@arm.com>,
	linux-kselftest@vger.kernel.org,
	 Shuah Khan <skhan@linuxfoundation.org>,
	Shuah Khan <shuah@kernel.org>,
	 kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org,
	 Luca Salabrino <luca.scalabrino@arm.com>
Subject: Re: [PATCH v14 00/39] arm64/sme: Initial support for the Scalable Matrix Extension
Date: Wed, 4 May 2022 10:55:21 +0530	[thread overview]
Message-ID: <CA+G9fYsRZKFXeiOQ0dp_-vL-3JimC5u75djvc1Ussv1cLsiUbA@mail.gmail.com> (raw)
In-Reply-To: <YnHANG5cM0CS9ffm@sirena.org.uk>

On Wed, 4 May 2022 at 05:22, Mark Brown <broonie@kernel.org> wrote:
>
> On Tue, May 03, 2022 at 06:23:40PM -0400, Qian Cai wrote:
> > On Tue, Apr 19, 2022 at 12:22:08PM +0100, Mark Brown wrote:
> > > This series provides initial support for the ARMv9 Scalable Matrix
> > > Extension (SME).  SME takes the approach used for vectors in SVE and
> > > extends this to provide architectural support for matrix operations.  A
> > > more detailed overview can be found in [1].
> >
> > Set CONFIG_ARM64_SME=n fixed a warning while running libhugetlbfs tests.
> >
> >         /*
> >          * There are several places where we assume that the order value is sane
> >          * so bail out early if the request is out of bound.
> >          */
> >         if (unlikely(order >= MAX_ORDER)) {
> >                 WARN_ON_ONCE(!(gfp & __GFP_NOWARN));
> >                 return NULL;
> >         }
>
> Ugh, right.  These variable sized register sets really don't map
> entirely cleanly onto the ptrace interface but now you point it
> out what the code has there is going to give a rather larger
> number than is sensible.  Not fully checked but does the below
> fix things?
>
> Thanks for your testing with this stuff, it's been really
> helpful.
>
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index 47d8a7472171..08c1cb43cf33 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -1447,8 +1447,8 @@ static const struct user_regset aarch64_regsets[] = {
>         },
>         [REGSET_ZA] = { /* SME ZA */
>                 .core_note_type = NT_ARM_ZA,
> -               .n = DIV_ROUND_UP(ZA_PT_ZA_SIZE(SVE_VQ_MAX), SVE_VQ_BYTES),
> -               .size = SVE_VQ_BYTES,
> +               .n = 1,
> +               .size = ZA_PT_SIZE(SVE_VQ_MAX),
>                 .align = SVE_VQ_BYTES,
>                 .regset_get = za_get,
>                 .set = za_set,

I have tested this patch but the warning did not fix.
Testing libhugetlbfs on qemu_arm64 triggering this warning.

Kernel warning:
-------------------
[   13.266791] kauditd_printk_skb: 1 callbacks suppressed
[   13.266794] audit: type=1701 audit(1651640394.652:25):
auid=4294967295 uid=0 gid=0 ses=4294967295 pid=463
comm=\"brk_near_huge\"
exe=\"/usr/lib/libhugetlbfs/tests/obj64/brk_near_huge\" sig=6 res=1
[   13.267376] ------------[ cut here ]------------
[   13.267378] WARNING: CPU: 2 PID: 463 at mm/page_alloc.c:5368
__alloc_pages+0x624/0xd50
[   13.269956] Modules linked in: crct10dif_ce rfkill fuse
[   13.270357] CPU: 2 PID: 463 Comm: brk_near_huge Not tainted
5.18.0-rc4-next-20220429 #1
[   13.270964] Hardware name: linux,dummy-virt (DT)
[   13.271315] pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   13.271841] pc : __alloc_pages+0x624/0xd50
[   13.272157] lr : alloc_pages+0xb8/0x170
[   13.272451] sp : ffff800008873630
[   13.272704] x29: ffff800008873630 x28: 000000000000000f x27: ffffb53cfad91650
[   13.273248] x26: ffff0000c57f2c00 x25: ffff800008873c58 x24: 000000000000000f
[   13.273788] x23: 0000000000000dc0 x22: 0000000000000000 x21: 000000000000000f
[   13.274327] x20: ffffb53cfc8189a0 x19: 0000000000040dc0 x18: 0000000000000000
[   13.274868] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[   13.275406] x14: 0000000000000000 x13: 0000000000000000 x12: ffff0000ff7f5b58
[   13.275945] x11: 0000000000000068 x10: ffffb53cfb77d000 x9 : ffffb53cf9d30e78
[   13.276485] x8 : fffffc00038e0001 x7 : dead000000000100 x6 : 0000000000000001
[   13.277021] x5 : 0000000000000000 x4 : ffff0000c55fe180 x3 : 0000000000000000
[   13.277559] x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000040dc0
[   13.278096] Call trace:
[   13.278285]  __alloc_pages+0x624/0xd50
[   13.278576]  alloc_pages+0xb8/0x170
[   13.278844]  kmalloc_order+0x40/0x100
[   13.279126]  kmalloc_order_trace+0x38/0x130
[   13.279445]  __kmalloc+0x37c/0x3e0
[   13.279707]  __regset_get+0xa0/0x104
[   13.279983]  regset_get_alloc+0x20/0x2c
[   13.280277]  elf_core_dump+0x3a8/0xd10
[   13.280567]  do_coredump+0xe50/0x138c
[   13.280850]  get_signal+0x860/0x920
[   13.281119]  do_notify_resume+0x184/0x1480
[   13.281428]  el0_svc+0xa8/0xc0
[   13.281666]  el0t_64_sync_handler+0xbc/0x140
[   13.281992]  el0t_64_sync+0x18c/0x190
[   13.282273] ---[ end trace 0000000000000000 ]---

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

url:
https://lkft.validation.linaro.org/scheduler/job/4983793#L831

Build link: https://builds.tuxbuild.com/28gVhSoYA4NRerhwD1gkY4QdHLt/

--
Linaro LKFT
https://lkft.linaro.org

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