CVE: CVE-2025-37754
Published: 2025-05-01
Description: In the Linux kernel, the following vulnerability has been resolved:

drm/i915/huc: Fix fence not released on early probe errors

HuC delayed loading fence, introduced with commit 27536e03271da
("drm/i915/huc: track delayed HuC load with a fence"), is registered with
object tracker early on driver probe but unregistered only from driver
remove, which is not called on early probe errors.  Since its memory is
allocated under devres, then released anyway, it may happen to be
allocated again to the fence and reused on future driver probes, resulting
in kernel warnings that taint the kernel:

<4> [309.731371] ------------[ cut here ]------------
<3> [309.731373] ODEBUG: init destroyed (active state 0) object: ffff88813d7dd2e0 object type: i915_sw_fence hint: sw_fence_dummy_notify+0x0/0x20 [i915]
<4> [309.731575] WARNING: CPU: 2 PID: 3161 at lib/debugobjects.c:612 debug_print_object+0x93/0xf0
...
<4> [309.731693] CPU: 2 UID: 0 PID: 3161 Comm: i915_module_loa Tainted: G     U             6.14.0-CI_DRM_16362-gf0fd77956987+ #1
...
<4> [309.731700] RIP: 0010:debug_print_object+0x93/0xf0
...
<4> [309.731728] Call Trace:
<4> [309.731730]  <TASK>
...
<4> [309.731949]  __debug_object_init+0x17b/0x1c0
<4> [309.731957]  debug_object_init+0x34/0x50
<4> [309.732126]  __i915_sw_fence_init+0x34/0x60 [i915]
<4> [309.732256]  intel_huc_init_early+0x4b/0x1d0 [i915]
<4> [309.732468]  intel_uc_init_early+0x61/0x680 [i915]
<4> [309.732667]  intel_gt_common_init_early+0x105/0x130 [i915]
<4> [309.732804]  intel_root_gt_init_early+0x63/0x80 [i915]
<4> [309.732938]  i915_driver_probe+0x1fa/0xeb0 [i915]
<4> [309.733075]  i915_pci_probe+0xe6/0x220 [i915]
<4> [309.733198]  local_pci_probe+0x44/0xb0
<4> [309.733203]  pci_device_probe+0xf4/0x270
<4> [309.733209]  really_probe+0xee/0x3c0
<4> [309.733215]  __driver_probe_device+0x8c/0x180
<4> [309.733219]  driver_probe_device+0x24/0xd0
<4> [309.733223]  __driver_attach+0x10f/0x220
<4> [309.733230]  bus_for_each_dev+0x7d/0xe0
<4> [309.733236]  driver_attach+0x1e/0x30
<4> [309.733239]  bus_add_driver+0x151/0x290
<4> [309.733244]  driver_register+0x5e/0x130
<4> [309.733247]  __pci_register_driver+0x7d/0x90
<4> [309.733251]  i915_pci_register_driver+0x23/0x30 [i915]
<4> [309.733413]  i915_init+0x34/0x120 [i915]
<4> [309.733655]  do_one_initcall+0x62/0x3f0
<4> [309.733667]  do_init_module+0x97/0x2a0
<4> [309.733671]  load_module+0x25ff/0x2890
<4> [309.733688]  init_module_from_file+0x97/0xe0
<4> [309.733701]  idempotent_init_module+0x118/0x330
<4> [309.733711]  __x64_sys_finit_module+0x77/0x100
<4> [309.733715]  x64_sys_call+0x1f37/0x2650
<4> [309.733719]  do_syscall_64+0x91/0x180
<4> [309.733763]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
<4> [309.733792]  </TASK>
...
<4> [309.733806] ---[ end trace [PII_REDACTED] ]---

That scenario is most easily reproducible with
igt@i915_module_load@reload-with-fault-injection.

Fix the issue by moving the cleanup step to driver release path.

(cherry picked from commit 795dbde92fe5c6996a02a5b579481de73035e7bf)
CVSS Score: 5.5 (MEDIUM)
References: https://git.kernel.org/stable/c/4bd4bf79bcfe101f0385ab81dbabb6e3f7d96c00; https://git.kernel.org/stable/c/9f5ef4a5eaa61a7a4ed31231da45deb85065397a; https://git.kernel.org/stable/c/c5a906806162aea62dbe5d327760ce3b7117ca17