CVE-2025-68244
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-16

Last updated on: 2025-12-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: drm/i915: Avoid lock inversion when pinning to GGTT on CHV/BXT+VTD On completion of i915_vma_pin_ww(), a synchronous variant of dma_fence_work_commit() is called. When pinning a VMA to GGTT address space on a Cherry View family processor, or on a Broxton generation SoC with VTD enabled, i.e., when stop_machine() is then called from intel_ggtt_bind_vma(), that can potentially lead to lock inversion among reservation_ww and cpu_hotplug locks. [86.861179] ====================================================== [86.861193] WARNING: possible circular locking dependency detected [86.861209] 6.15.0-rc5-CI_DRM_16515-gca0305cadc2d+ #1 Tainted: G U [86.861226] ------------------------------------------------------ [86.861238] i915_module_loa/1432 is trying to acquire lock: [86.861252] ffffffff83489090 (cpu_hotplug_lock){++++}-{0:0}, at: stop_machine+0x1c/0x50 [86.861290] but task is already holding lock: [86.861303] ffffc90002e0b4c8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915] [86.862233] which lock already depends on the new lock. [86.862251] the existing dependency chain (in reverse order) is: [86.862265] -> #5 (reservation_ww_class_mutex){+.+.}-{3:3}: [86.862292] dma_resv_lockdep+0x19a/0x390 [86.862315] do_one_initcall+0x60/0x3f0 [86.862334] kernel_init_freeable+0x3cd/0x680 [86.862353] kernel_init+0x1b/0x200 [86.862369] ret_from_fork+0x47/0x70 [86.862383] ret_from_fork_asm+0x1a/0x30 [86.862399] -> #4 (reservation_ww_class_acquire){+.+.}-{0:0}: [86.862425] dma_resv_lockdep+0x178/0x390 [86.862440] do_one_initcall+0x60/0x3f0 [86.862454] kernel_init_freeable+0x3cd/0x680 [86.862470] kernel_init+0x1b/0x200 [86.862482] ret_from_fork+0x47/0x70 [86.862495] ret_from_fork_asm+0x1a/0x30 [86.862509] -> #3 (&mm->mmap_lock){++++}-{3:3}: [86.862531] down_read_killable+0x46/0x1e0 [86.862546] lock_mm_and_find_vma+0xa2/0x280 [86.862561] do_user_addr_fault+0x266/0x8e0 [86.862578] exc_page_fault+0x8a/0x2f0 [86.862593] asm_exc_page_fault+0x27/0x30 [86.862607] filldir64+0xeb/0x180 [86.862620] kernfs_fop_readdir+0x118/0x480 [86.862635] iterate_dir+0xcf/0x2b0 [86.862648] __x64_sys_getdents64+0x84/0x140 [86.862661] x64_sys_call+0x1058/0x2660 [86.862675] do_syscall_64+0x91/0xe90 [86.862689] entry_SYSCALL_64_after_hwframe+0x76/0x7e [86.862703] -> #2 (&root->kernfs_rwsem){++++}-{3:3}: [86.862725] down_write+0x3e/0xf0 [86.862738] kernfs_add_one+0x30/0x3c0 [86.862751] kernfs_create_dir_ns+0x53/0xb0 [86.862765] internal_create_group+0x134/0x4c0 [86.862779] sysfs_create_group+0x13/0x20 [86.862792] topology_add_dev+0x1d/0x30 [86.862806] cpuhp_invoke_callback+0x4b5/0x850 [86.862822] cpuhp_issue_call+0xbf/0x1f0 [86.862836] __cpuhp_setup_state_cpuslocked+0x111/0x320 [86.862852] __cpuhp_setup_state+0xb0/0x220 [86.862866] topology_sysfs_init+0x30/0x50 [86.862879] do_one_initcall+0x60/0x3f0 [86.862893] kernel_init_freeable+0x3cd/0x680 [86.862908] kernel_init+0x1b/0x200 [86.862921] ret_from_fork+0x47/0x70 [86.862934] ret_from_fork_asm+0x1a/0x30 [86.862947] -> #1 (cpuhp_state_mutex){+.+.}-{3:3}: [86.862969] __mutex_lock+0xaa/0xed0 [86.862982] mutex_lock_nested+0x1b/0x30 [86.862995] __cpuhp_setup_state_cpuslocked+0x67/0x320 [86.863012] __cpuhp_setup_state+0xb0/0x220 [86.863026] page_alloc_init_cpuhp+0x2d/0x60 [86.863041] mm_core_init+0x22/0x2d0 [86.863054] start_kernel+0x576/0xbd0 [86.863068] x86_64_start_reservations+0x18/0x30 [86.863084] x86_64_start_kernel+0xbf/0x110 [86.863098] common_startup_64+0x13e/0x141 [86.863114] -> #0 (cpu_hotplug_lock){++++}-{0:0}: [86.863135] __lock_acquire+0x16 ---truncated---
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Meta Information
Published
2025-12-16
Last Modified
2025-12-18
Generated
2026-05-07
AI Q&A
2025-12-16
EPSS Evaluated
2026-05-05
NVD
CVE-2025-68244
EUVD
EUVD-2025-203652
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability involves a lock inversion issue in the Linux kernel's i915 graphics driver when pinning a virtual memory area (VMA) to the Global Graphics Translation Table (GGTT) address space on certain Intel processors (Cherry View family or Broxton generation SoC with VTD enabled). The problem occurs because a synchronous call to dma_fence_work_commit() leads to a circular locking dependency between reservation_ww and cpu_hotplug locks, which can cause warnings and potential deadlocks in the kernel.


How can this vulnerability impact me? :

This vulnerability can lead to lock inversion and circular locking dependencies in the kernel, potentially causing kernel warnings and deadlocks. This may result in system instability or crashes when the affected graphics driver operations are performed on the specified hardware platforms.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring kernel logs for warnings about circular locking dependencies related to the i915 module, specifically messages like 'WARNING: possible circular locking dependency detected' involving cpu_hotplug_lock and reservation_ww_class_mutex. You can check the kernel log using the command: dmesg | grep -i 'circular locking dependency' or dmesg | grep -i i915.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation steps include updating the Linux kernel to a version where this vulnerability is resolved, as the issue is fixed in the kernel code related to drm/i915. Until an update is applied, monitoring for the warning messages and avoiding workloads that trigger the lock inversion on affected hardware (Cherry View processors or Broxton SoCs with VTD enabled) may reduce risk.


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