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

Naresh Kamboju
2022-05-04T05:25:36Z

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