CVE - CVE-2023-52486

CVE-ID
CVE-2023-52486	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: drm: Don't unref the same fb many times by mistake due to deadlock handling If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl() we proceed to unref the fb and then retry the whole thing from the top. But we forget to reset the fb pointer back to NULL, and so if we then get another error during the retry, before the fb lookup, we proceed the unref the same fb again without having gotten another reference. The end result is that the fb will (eventually) end up being freed while it's still in use. Reset fb to NULL once we've unreffed it to avoid doing it again until we've done another fb lookup. This turned out to be pretty easy to hit on a DG2 when doing async flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I saw that drm_closefb() simply got stuck in a busy loop while walking the framebuffer list. Fortunately I was able to convince it to oops instead, and from there it was easier to track down the culprit.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/376e21a9e4c2c63ee5d8d3aa74be5082c3882229 URL:https://git.kernel.org/stable/c/376e21a9e4c2c63ee5d8d3aa74be5082c3882229 MISC:https://git.kernel.org/stable/c/62f2e79cf9f4f47cc9dea9cebdf58d9f7b5695e0 URL:https://git.kernel.org/stable/c/62f2e79cf9f4f47cc9dea9cebdf58d9f7b5695e0 MISC:https://git.kernel.org/stable/c/9dd334a8245011ace45e53298175c7b659edb3e7 URL:https://git.kernel.org/stable/c/9dd334a8245011ace45e53298175c7b659edb3e7 MISC:https://git.kernel.org/stable/c/b4af63da9d94986c529d74499fdfe44289acd551 URL:https://git.kernel.org/stable/c/b4af63da9d94986c529d74499fdfe44289acd551 MISC:https://git.kernel.org/stable/c/bfd0feb1b109cb63b87fdcd00122603787c75a1a URL:https://git.kernel.org/stable/c/bfd0feb1b109cb63b87fdcd00122603787c75a1a MISC:https://git.kernel.org/stable/c/cb4daf271302d71a6b9a7c01bd0b6d76febd8f0c URL:https://git.kernel.org/stable/c/cb4daf271302d71a6b9a7c01bd0b6d76febd8f0c MISC:https://git.kernel.org/stable/c/d7afdf360f4ac142832b098b4de974e867cc063c URL:https://git.kernel.org/stable/c/d7afdf360f4ac142832b098b4de974e867cc063c MISC:https://git.kernel.org/stable/c/f55261469be87c55df13db76dc945f6bcd825105 URL:https://git.kernel.org/stable/c/f55261469be87c55df13db76dc945f6bcd825105
Assigning CNA
kernel.org
Date Record Created
20240220	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240220)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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