Advisory Published
Updated

CVE-2025-21880: drm/xe/userptr: fix EFAULT handling

First published: Thu Mar 27 2025(Updated: )

In the Linux kernel, the following vulnerability has been resolved: drm/xe/userptr: fix EFAULT handling Currently we treat EFAULT from hmm_range_fault() as a non-fatal error when called from xe_vm_userptr_pin() with the idea that we want to avoid killing the entire vm and chucking an error, under the assumption that the user just did an unmap or something, and has no intention of actually touching that memory from the GPU. At this point we have already zapped the PTEs so any access should generate a page fault, and if the pin fails there also it will then become fatal. However it looks like it's possible for the userptr vma to still be on the rebind list in preempt_rebind_work_func(), if we had to retry the pin again due to something happening in the caller before we did the rebind step, but in the meantime needing to re-validate the userptr and this time hitting the EFAULT. This explains an internal user report of hitting: [ 191.738349] WARNING: CPU: 1 PID: 157 at drivers/gpu/drm/xe/xe_res_cursor.h:158 xe_pt_stage_bind.constprop.0+0x60a/0x6b0 [xe] [ 191.738551] Workqueue: xe-ordered-wq preempt_rebind_work_func [xe] [ 191.738616] RIP: 0010:xe_pt_stage_bind.constprop.0+0x60a/0x6b0 [xe] [ 191.738690] Call Trace: [ 191.738692] <TASK> [ 191.738694] ? show_regs+0x69/0x80 [ 191.738698] ? __warn+0x93/0x1a0 [ 191.738703] ? xe_pt_stage_bind.constprop.0+0x60a/0x6b0 [xe] [ 191.738759] ? report_bug+0x18f/0x1a0 [ 191.738764] ? handle_bug+0x63/0xa0 [ 191.738767] ? exc_invalid_op+0x19/0x70 [ 191.738770] ? asm_exc_invalid_op+0x1b/0x20 [ 191.738777] ? xe_pt_stage_bind.constprop.0+0x60a/0x6b0 [xe] [ 191.738834] ? ret_from_fork_asm+0x1a/0x30 [ 191.738849] bind_op_prepare+0x105/0x7b0 [xe] [ 191.738906] ? dma_resv_reserve_fences+0x301/0x380 [ 191.738912] xe_pt_update_ops_prepare+0x28c/0x4b0 [xe] [ 191.738966] ? kmemleak_alloc+0x4b/0x80 [ 191.738973] ops_execute+0x188/0x9d0 [xe] [ 191.739036] xe_vm_rebind+0x4ce/0x5a0 [xe] [ 191.739098] ? trace_hardirqs_on+0x4d/0x60 [ 191.739112] preempt_rebind_work_func+0x76f/0xd00 [xe] Followed by NPD, when running some workload, since the sg was never actually populated but the vma is still marked for rebind when it should be skipped for this special EFAULT case. This is confirmed to fix the user report. v2 (MattB): - Move earlier. v3 (MattB): - Update the commit message to make it clear that this indeed fixes the issue. (cherry picked from commit 6b93cb98910c826c2e2004942f8b060311e43618)

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Kernel

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Frequently Asked Questions

  • What is the severity of CVE-2025-21880?

    CVE-2025-21880 is considered a medium severity vulnerability in the Linux kernel.

  • How do I fix CVE-2025-21880?

    To mitigate CVE-2025-21880, ensure that you update your Linux kernel to the latest patched version.

  • What are the potential impacts of CVE-2025-21880?

    The potential impact of CVE-2025-21880 includes non-fatal errors during memory operations in the Linux kernel.

  • Is my system vulnerable to CVE-2025-21880?

    Systems running affected versions of the Linux kernel may be vulnerable to CVE-2025-21880, so checking your kernel version is advised.

  • What kind of systems are affected by CVE-2025-21880?

    CVE-2025-21880 affects systems using the Linux kernel specifically with the drm/xe subsystem.

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