Subject: CVE-2024-49989: drm/amd/display: fix double free issue during amdgpu module unload

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: fix double free issue during amdgpu module unload

Flexible endpoints use DIGs from available inflexible endpoints,
so only the encoders of inflexible links need to be freed.
Otherwise, a double free issue may occur when unloading the
amdgpu module.

[  279.190523] RIP: 0010:__slab_free+0x152/0x2f0
[  279.190577] Call Trace:
[  279.190580]  <TASK>
[  279.190582]  ? show_regs+0x69/0x80
[  279.190590]  ? die+0x3b/0x90
[  279.190595]  ? do_trap+0xc8/0xe0
[  279.190601]  ? do_error_trap+0x73/0xa0
[  279.190605]  ? __slab_free+0x152/0x2f0
[  279.190609]  ? exc_invalid_op+0x56/0x70
[  279.190616]  ? __slab_free+0x152/0x2f0
[  279.190642]  ? asm_exc_invalid_op+0x1f/0x30
[  279.190648]  ? dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[  279.191096]  ? __slab_free+0x152/0x2f0
[  279.191102]  ? dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[  279.191469]  kfree+0x260/0x2b0
[  279.191474]  dcn10_link_encoder_destroy+0x19/0x30 [amdgpu]
[  279.191821]  link_destroy+0xd7/0x130 [amdgpu]
[  279.192248]  dc_destruct+0x90/0x270 [amdgpu]
[  279.192666]  dc_destroy+0x19/0x40 [amdgpu]
[  279.193020]  amdgpu_dm_fini+0x16e/0x200 [amdgpu]
[  279.193432]  dm_hw_fini+0x26/0x40 [amdgpu]
[  279.193795]  amdgpu_device_fini_hw+0x24c/0x400 [amdgpu]
[  279.194108]  amdgpu_driver_unload_kms+0x4f/0x70 [amdgpu]
[  279.194436]  amdgpu_pci_remove+0x40/0x80 [amdgpu]
[  279.194632]  pci_device_remove+0x3a/0xa0
[  279.194638]  device_remove+0x40/0x70
[  279.194642]  device_release_driver_internal+0x1ad/0x210
[  279.194647]  driver_detach+0x4e/0xa0
[  279.194650]  bus_remove_driver+0x6f/0xf0
[  279.194653]  driver_unregister+0x33/0x60
[  279.194657]  pci_unregister_driver+0x44/0x90
[  279.194662]  amdgpu_exit+0x19/0x1f0 [amdgpu]
[  279.194939]  __do_sys_delete_module.isra.0+0x198/0x2f0
[  279.194946]  __x64_sys_delete_module+0x16/0x20
[  279.194950]  do_syscall_64+0x58/0x120
[  279.194954]  entry_SYSCALL_64_after_hwframe+0x6e/0x76
[  279.194980]  </TASK>

The Linux kernel CVE team has assigned CVE-2024-49989 to this issue.

Affected and fixed versions
===========================

	Fixed in 6.6.55 with commit cf6f3ebd6312
	Fixed in 6.10.14 with commit 7af9e6fa63db
	Fixed in 6.11.3 with commit 3c0ff4de45ce
	Fixed in 6.12-rc1 with commit 20b5a8f9f467

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-49989
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/amd/display/dc/link/link_factory.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/cf6f3ebd6312d465fee096d1f58089b177c7c67f
	https://git.kernel.org/stable/c/7af9e6fa63dbd43a61d4ecc8f59426596a75e507
	https://git.kernel.org/stable/c/3c0ff4de45ce2c5f7997a1ffa6eefee4b79e6b58
	https://git.kernel.org/stable/c/20b5a8f9f4670a8503aa9fa95ca632e77c6bf55d