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From:   David Mozes <david.mozes@silk.us>
To:     Wei Liu <wei.liu@kernel.org>
CC:     David Moses <mosesster@gmail.com>,
        Michael Kelley <mikelley@microsoft.com>,
        =?windows-1255?B?+uXu+CDg4eXo4eXs?= <tomer432100@gmail.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] x86/hyper-v: guard against cpu mask changes in
 hyperv_flush_tlb_others()
Thread-Topic: [PATCH] x86/hyper-v: guard against cpu mask changes in
 hyperv_flush_tlb_others()
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Date:   Sun, 22 Aug 2021 16:25:19 +0000
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This is not visible since we need a very high load to reproduce.=20
We have tried a lot but can't achieve the desired load=20
On our kernel with less load, it is not reproducible as well.

-----Original Message-----
From: Wei Liu <wei.liu@kernel.org>=20
Sent: Sunday, August 22, 2021 6:25 PM
To: David Mozes <david.mozes@silk.us>
Cc: David Moses <mosesster@gmail.com>; Wei Liu <wei.liu@kernel.org>; Michae=
l Kelley <mikelley@microsoft.com>; =FA=E5=EE=F8 =E0=E1=E5=E8=E1=E5=EC <tome=
r432100@gmail.com>; linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.=
org
Subject: Re: [PATCH] x86/hyper-v: guard against cpu mask changes in hyperv_=
flush_tlb_others()

On Thu, Aug 19, 2021 at 07:55:06AM +0000, David Mozes wrote:
> Hi Wei ,
> I move the print cpumask to other two places after the treatment on the e=
mpty mask see below
> And I got the folwing:
>=20
>=20
> Aug 19 02:01:51 c-node05 kernel: [25936.562674] Hyper-V: ERROR_HYPERV2: c=
pu_last=3D
> Aug 19 02:01:51 c-node05 kernel: [25936.562686] WARNING: CPU: 11 PID: 564=
32 at arch/x86/include/asm/mshyperv.h:301 hyperv_flush_tlb_others+0x23f/0x7=
b0
>=20
> So we got empty on different place on the code .
> Let me know if you need further information from us.
> How you sagest to handle this situation?
>=20

Please find a way to reproduce this issue with upstream kernels.

Thanks,
Wei.