Bug 2521458 (CVE-2026-74721) - CVE-2026-74721 kernel: accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages()
Summary: CVE-2026-74721 kernel: accel/amxdna: Fix page-insertion errors in amdxdna_ins...
Keywords:
Status: NEW
Alias: CVE-2026-74721
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-22 15:46 UTC by OSIDB Bzimport
Modified: 2026-08-24 18:18 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-22 15:46:34 UTC
In the Linux kernel, the following vulnerability has been resolved:

accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages()

Two error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma)
before returning an error code to the caller.  This is incorrect:
amdxdna_gem_obj_mmap() registers an HMM interval notifier before calling
amdxdna_insert_pages(), and on a hard error it jumps to hmm_unreg to undo
that registration.  Calling vm_ops->close() manually — which drops the
shmem pages_pin_count and the GEM object reference that backs the VMA —
before the mmap syscall has even returned causes those resources to be
released while the VMA is still alive.  The kernel VMA teardown will call
vm_ops->close() a second time when the process later unmaps the range,
producing a reference count underflow.

Replace both hard-error returns with a deferred-fault approach that keeps
the VMA alive and retries page insertion through the HMM range-fault path.


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