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From: Hillf Danton <hdanton@sina.com>
To: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: robin.murphy@arm.com, joro@8bytes.org, will@kernel.org,
	iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
	Li Bin <huawei.libin@huawei.com>, Xie XiuQi <xiexiuqi@huawei.com>,
	Yang Yingliang <yangyingliang@huawei.com>
Subject: Re: [PATCH] iommu: Avoid softlockup and rcu stall in fq_flush_timeout().
Date: Thu, 16 Feb 2023 19:44:28 +0800	[thread overview]
Message-ID: <20230216114428.1622-1-hdanton@sina.com> (raw)
In-Reply-To: <65da1862-364b-9500-4be7-a463a12e6a7f@bytedance.com>

On Thu, 16 Feb 2023 19:02:59 +0800 Peng Zhang <zhangpeng.00@bytedance.com>
> 在 2023/2/16 16:49, Hillf Danton 写道:
> > On Thu, 16 Feb 2023 15:11:48 +0800 Peng Zhang <zhangpeng.00@bytedance.com>
> >> There is softlockup under fio pressure test with smmu enabled:
> >> watchdog: BUG: soft lockup - CPU#81 stuck for 22s!  [swapper/81:0]
> > 
> > What is your kernel version?
>
> Rcu stall occurs in kernel version 5.4.

Info like 5.4 and the number of CPUs helps understand your work.

> The test where the softlockup happened was not done by me, so I don't 
> know the kernel version.
> However, it is the same as the code logic of fq_flush_timeout in the 
> mainline kernel.

Could it be reproduced with mainline and a system with two CPUs?

  reply	other threads:[~2023-02-16 11:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-16  7:11 [PATCH] iommu: Avoid softlockup and rcu stall in fq_flush_timeout() Peng Zhang
2023-02-16  8:49 ` Hillf Danton
2023-02-16 11:02   ` Peng Zhang
2023-02-16 11:44     ` Hillf Danton [this message]
2023-04-10 22:22 ` Jerry Snitselaar
2023-04-18 10:41   ` Vasant Hegde
2023-04-28  5:44     ` Vasant Hegde
2023-05-22 14:58       ` Joerg Roedel
2023-05-22 15:18         ` Jerry Snitselaar
2023-05-22 15:35           ` John Garry

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