s390/ism: fix concurrency management in ism_cmd()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-39726
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-09-05 18:15:50 UTC
Updated2026-07-30 06:23:43 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: s390/ism: fix concurrency management in ism_cmd() The s390x ISM device data sheet clearly states that only one request-response sequence is allowable per ISM function at any point in time. Unfortunately as of today the s390/ism driver in Linux does not honor that requirement. This patch aims to rectify that. This problem was discovered based on Aliaksei's bug report which states that for certain workloads the ISM functions end up entering error state (with PEC 2 as seen from the logs) after a while and as a consequence connections handled by the respective function break, and for future connection requests the ISM device is not considered -- given it is in a dysfunctional state. During further debugging PEC 3A was observed as well. A kernel message like [ 1211.244319] zpci: 061a:00:00.0: Event 0x2 reports an error for PCI function 0x61a is a reliable indicator of the stated function entering error state with PEC 2. Let me also point out that a kernel message like [ 1211.244325] zpci: 061a:00:00.0: The ism driver bound to the device does not support error recovery is a reliable indicator that the ISM function won't be auto-recovered because the ISM driver currently lacks support for it. On a technical level, without this synchronization, commands (inputs to the FW) may be partially or fully overwritten (corrupted) by another CPU trying to issue commands on the same function. There is hard evidence that this can lead to DMB token values being used as DMB IOVAs, leading to PEC 2 PCI events indicating invalid DMA. But this is only one of the failure modes imaginable. In theory even completely losing one command and executing another one twice and then trying to interpret the outputs as if the command we intended to execute was actually executed and not the other one is also possible. Frankly, I don't feel confident about providing an exhaustive list of possible consequences.

Risk And Classification

Primary CVSS: v3.1 4.7 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-362

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary4.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 faf44487dfc80817f178dc8de7a0b73f960d019b git Not specified
CNA Linux Linux affected 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 1194ad0d44d66b273a02a3a22882dc863a68d764 git Not specified
CNA Linux Linux affected 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 fafaa4982bedb5532f5952000f714a3e63023f40 git Not specified
CNA Linux Linux affected 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 897e8601b9cff1d054cdd53047f568b0e1995726 git Not specified
CNA Linux Linux affected 4.19 Not specified
CNA Linux Linux unaffected 4.19 semver Not specified
CNA Linux Linux unaffected 6.6.101 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.41 6.12.* semver Not specified
CNA Linux Linux unaffected 6.15.9 6.15.* semver Not specified
CNA Linux Linux unaffected 6.16 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/faf44487dfc80817f178dc8de7a0b73f960d019b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/897e8601b9cff1d054cdd53047f568b0e1995726 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/1194ad0d44d66b273a02a3a22882dc863a68d764 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/fafaa4982bedb5532f5952000f714a3e63023f40 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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