CVE-2023-53501

iommu/amd/iommu_v2: Fix pasid_state refcount dec hit 0 warning on pasid unbind

MEDIUM
4.7
CVSS Score
Published: October 1, 2025 at 11:45 AM UTC
Updated: June 17, 2026 at 06:45 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM4.7
Exploit prediction
EPSS 0.1%

Description

In the Linux kernel, the following vulnerability has been resolved: iommu/amd/iommu_v2: Fix pasid_state refcount dec hit 0 warning on pasid unbind When unbinding pasid - a race condition exists vs outstanding page faults. To prevent this, the pasid_state object contains a refcount. * set to 1 on pasid bind * incremented on each ppr notification start * decremented on each ppr notification done * decremented on pasid unbind Since refcount_dec assumes that refcount will never reach 0: the current implementation causes the following to be invoked on pasid unbind: REFCOUNT_WARN("decrement hit 0; leaking memory") Fix this issue by changing refcount_dec to refcount_dec_and_test to explicitly handle refcount=1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.15 ≤ v < 5.15.1325.15 ≤ v < 6.1.535.15 ≤ v < 6.4.165.15 ≤ v < 6.5.35.15 ≤ v < 6.65.16 ≤ v < 6.1.536.2 ≤ v < 6.4.166.5 ≤ v < 6.5.35.158bc54824da4e8fcf0ed679cf09ac32f23d83254a
Vendor states this is fixed in 13ed255248dfbbb7f23f9170c7a537fb9ca22c73 (fixed)
Vendor states this is fixed in 534103bcd52ca9c1fecbc70e717b4a538dc4ded8 (fixed)
Vendor states this is fixed in 98d86bf32187db27946ca817c2467a5f2f7aa02f (fixed)
Vendor states this is fixed in 9ccc51be3126b25cfe9351dbffde946c925cc28a (fixed)
Vendor states this is fixed in a50d60b8f2aff46dd7c7edb4a5835cdc4d432c22 (fixed)
Vendor states this is fixed in 5.15 (unaffected)
Vendor states this is fixed in 5.15.132 (unaffected)
Vendor states this is fixed in 6.1.53 (unaffected)
Vendor states this is fixed in 6.4.16 (unaffected)
Vendor states this is fixed in 6.5.3 (unaffected)
Vendor states this is fixed in 6.6 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-Other

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