CVE-2026-89994: dmaengine: fsl-edma: tracing: no ptr dereference during log output
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: fsl-edma: tracing: no ptr dereference during log output
The fsl edma events store a pointer to a struct fsledmaengine in the ringbuffer and dereference it when a log entry is printed. At this time, the pointer may no longer be valid.
Event injection can be used to trigger a crash:
$ cd /sys/kernel/tracing $ echo 'value = 0' > events/fsledma/edmawriteb/inject $ cat trace
The log output needs only edma->membase. Add a membase field at the end of the event and use the new field for log output. Keep the existing fields for backward compatibility.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
What access is needed to trigger the crash?
The described trigger uses trace event injection through /sys/kernel/tracing and then reads the trace output. An attacker would need access sufficient to write the fsl_edma event's inject control and read the tracing buffer.
Is this limited to systems using the fsl-edma trace events?
The issue is in fsl-edma tracing event output and specifically affects log entries that retain and later dereference a pointer to struct fsl_edma_engine. Systems without use of the affected fsl-edma tracing events are not described as having this trigger.
What is the immediate mitigation if the fix cannot be deployed?
Restrict access to the kernel tracing filesystem, particularly the fsl_edma event injection interface under /sys/kernel/tracing. Avoid injecting fsl_edma events and reading trace output in a way that exercises the affected event formatting.
How can an administrator identify a potentially affected configuration?
Check whether /sys/kernel/tracing/events/fsl_edma/edma_writeb/inject is present and whether users can write to it. The documented reproduction injects a value into that file and then reads the trace buffer with cat trace.