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From: w15303746062  <w15303746062@163.com>
To: "Christian König" <christian.koenig@amd.com>
Cc: maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch,
	sumit.semwal@linaro.org, jeffy.chen@rock-chips.com,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org,
	"Mingyu Wang" <25181214217@stu.xidian.edu.cn>,
	stable@vger.kernel.org
Subject: Re:Re: [PATCH] drm/prime: Fix unsupervised rb_tree corruption in drm_prime_remove_buf_handle
Date: Thu, 28 May 2026 20:40:44 +0800 (CST)	[thread overview]
Message-ID: <6d351ca7.9904.19e6e99f765.Coremail.w15303746062@163.com> (raw)
In-Reply-To: <0e12ce28-f5b7-4ffa-849c-df9ad1796e22@amd.com>

Hi Christian,

Thank you for the review and for catching this. You are absolutely right, and my analysis was flawed. Adding the lock inside `drm_prime_remove_buf_handle` would indeed cause a recursive deadlock.

The syzkaller crash was originally triggered on the v6.18 kernel. When investigating, I checked the latest mainline source for `drm_prime_remove_buf_handle` itself. Since I didn't see any synchronization changes within that specific function, I incorrectly assumed the concurrency issue was still completely unhandled, failing to notice that the upstream tree properly holds the lock in the caller (`drm_gem_object_release_handle`).

I will dive deeper into the code to see if there is still any hidden race condition under the current locking scheme, or if this is strictly a legacy issue that might only require a stable-tree backport. If a fix is still warranted, I will send a v2 patch.

Thanks again for your time and guidance!

Best regards,
Mingyu Wang

  reply	other threads:[~2026-05-28 12:42 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-28  8:29 w15303746062
2026-05-28  9:14 ` Christian König
2026-05-28 12:40   ` w15303746062 [this message]
2026-05-28 13:29   ` [PATCH v2] drm/prime: fix dangling dmabuf entries after handle release w15303746062
2026-05-28 13:32     ` Christian König
2026-05-28 13:49       ` w15303746062
2026-05-29  6:45         ` Christian König
2026-05-29 11:45           ` w15303746062
2026-05-31  7:54 ` [PATCH] drm/prime: Fix unsupervised rb_tree corruption in drm_prime_remove_buf_handle kernel test robot

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