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From: Nicolin Chen <nicolinc@nvidia.com>
To: Pengfei Xu <pengfei.xu@intel.com>
Cc: <jgg@nvidia.com>, <kevin.tian@intel.com>, <yi.l.liu@intel.com>,
	<iommu@lists.linux.dev>, <heng.su@intel.com>, <lkp@intel.com>
Subject: Re: [Syzkaller & bisect] There is WARNING in iopt_remove_access in upstream patch "iommufd/selftest: Add IOMMU_TEST_OP_ACCESS_REPLACE_IOAS coverage"
Date: Sun, 25 Jun 2023 11:55:02 -0700	[thread overview]
Message-ID: <ZJiNhhve1qxOfKtV@Asurada-Nvidia> (raw)
In-Reply-To: <ZJgJOClwU+d78rji@xpf.sh.intel.com>

On Sun, Jun 25, 2023 at 05:30:32PM +0800, Pengfei Xu wrote:

> > It turns out to be a bug in the new iommufd_access_change_pt()
> > that does iopt_add_access() prior to __iommufd_access_detach().
> > However, iopt_add_access() overrides access->iopt_access_list_id
> > being read by the following __iommufd_access_detach(). Thus, it
> > triggers the WARNING.
> 
> Thanks a lot for your analysis and fixed patch!
> I have installed your below patch on top of previous reproduced kernel.
> And ran the reproduced binary in previous VM more than 1 hour, this issue
> could not be reproduced, result show that it's fixed.
> The bzImage with below patch is in link:
> https://github.com/xupengfe/syzkaller_logs/blob/main/230614_070652_iopt_remove_access/bzImage_fix.gz

Thanks for retesting!

I've squashed this into the new version of my replace() series.

Nicolin

      reply	other threads:[~2023-06-25 18:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-15  2:23 [Syzkaller & bisect] There is WARNING in iopt_remove_access in upstream patch "iommufd/selftest: Add IOMMU_TEST_OP_ACCESS_REPLACE_IOAS coverage" Pengfei Xu
2023-06-23 22:10 ` Nicolin Chen
2023-06-25  9:30   ` Pengfei Xu
2023-06-25 18:55     ` Nicolin Chen [this message]

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