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From: Zheng Wang <zyytlz.wz@163.com>
To: zhi.a.wang@intel.com
Cc: 1002992920@qq.com, airlied@gmail.com, airlied@linux.ie,
	alex000young@gmail.com, dri-devel@lists.freedesktop.org,
	gregkh@linuxfoundation.org, hackerzheng666@gmail.com,
	intel-gfx@lists.freedesktop.org,
	intel-gvt-dev@lists.freedesktop.org,
	joonas.lahtinen@linux.intel.com, linux-kernel@vger.kernel.org,
	security@kernel.org, tvrtko.ursulin@linux.intel.com,
	zhenyuw@linux.intel.com, zyytlz.wz@163.com
Subject: Re: [Intel-gfx] [PATCH v3] drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
Date: Mon, 19 Dec 2022 17:21:39 +0800	[thread overview]
Message-ID: <20221219092139.222456-1-zyytlz.wz@163.com> (raw)
In-Reply-To: <11728bc1-7b59-1623-b517-d1a0d57eb275@intel.com>

Wang, Zhi A <zhi.a.wang@intel.com> 于2022年12月19日周一 16:22写道：

>
> I think it is a case-by-case thing. For example:
>
> The current scenario in this function looks like below:
>
> caller pass spt a
> function
>         alloc spt b
>         something error
>         free spt a
>         return error
>
> The problem is: the function wrongly frees the spt a instead free what
> it allocates.

Thanks for your clear explaination. It’s really helpfult to me.
I think I might know how to fix now.

> A proper fix should be:
>
> caller pass spt a
> function
>         alloc spt b
>         something error
>         *free spt b*
>         return error
>
As it's a case-by-case thing, I'll extract the un-done-mapping-dma part from
ppgtt_invalidate_spt and put it in error path. Then I'll add the code of freeing
new allocated spt. If I misunderstand your meaning, feel free to let me know.
Working on a new fix now.

Best regards,
Zheng Wang


  reply	other threads:[~2022-12-19  9:37 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <tencent_ED24158E83CB9885E8BDD173EB5896B51906@qq.com>
2022-09-19  9:30 ` [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry Jani Nikula
2022-09-19  9:55   ` Zheng Hacker
2022-09-21  9:13   ` Zheng Hacker
2022-09-28  3:33     ` [PATCH] drm/i915/gvt: fix double free " Zheng Wang
2022-10-02 14:18       ` Greg KH
2022-10-03  4:36         ` Zheng Hacker
2022-10-06 16:58       ` [PATCH v2] " Zheng Wang
2022-10-06 19:23         ` Greg KH
2022-10-07  0:39           ` Zheng Hacker
2022-10-07  1:37           ` [PATCH v3] " Zheng Wang
2022-10-27  0:01             ` Dave Airlie
2022-10-27  3:26               ` Zheng Hacker
2022-10-27  5:12                 ` Dave Airlie
2022-10-30 15:10                   ` Zheng Hacker
2022-12-15 10:47                   ` Joonas Lahtinen
2022-12-15 11:33                     ` Wang, Zhi A
2022-12-15 13:26                       ` Zheng Hacker
2022-12-19  7:57                       ` [Intel-gfx] " Zheng Wang
2022-12-19  8:22                         ` Wang, Zhi A
2022-12-19  9:21                           ` Zheng Wang [this message]
2022-12-19 12:46                           ` [PATCH v4] [PATCH v4] " Zheng Wang
2022-12-19 12:52                           ` [RESEND PATCH " Zheng Wang
2022-12-20  8:22                             ` Zhenyu Wang
2022-12-20  9:03                               ` Zheng Hacker
2022-12-20  9:40                           ` [PATCH v5] " Zheng Wang
2022-12-21  2:58                             ` Zhenyu Wang
2022-12-21  5:01                               ` Zheng Hacker
2022-12-29 16:56                           ` [PATCH v6] " Zheng Wang

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