Bug 2513227 (CVE-2026-68175)

Summary: CVE-2026-68175 kernel: tracing: Fix resource leak on mmiotrace trace_pipe close
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `mmiotrace` tracer. A local user could repeatedly read from the `trace_pipe` file without fully completing the read operation. This improper handling of resource cleanup leads to a significant memory leak and leaves stale references. The continuous accumulation of these leaked resources can result in a Denial of Service (DoS) due to system instability or exhaustion of available memory.
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Description OSIDB Bzimport 2026-08-10 12:25:56 UTC 
In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix resource leak on mmiotrace trace_pipe close

The mmiotrace tracer was added May 12th 2008. At that time, resources
created in pipe_open() could not be freed because there was not
pipe_close function pointer of the tracer. The pipe_close function pointer
was added in December 7th, 2009, but the mmiotrace tracer was not updated.

mmio_pipe_open() allocates a header_iter and takes a pci_dev reference
when trace_pipe is opened. mmio_close() frees them, but it was only
wired to the tracer's .close callback.

tracing_release_pipe() invokes .pipe_close, not .close, when the
trace_pipe file is released. As a result, closing trace_pipe with the
mmiotrace tracer active leaked the header_iter allocation and left a
stale pci_dev reference.

Set .pipe_close to mmio_close, matching how function_graph wires both
callbacks to the same handler.

Note, if the trace_pipe is read to completion, it will clean up the
resources, but if one were to run:

  # head -n 1 /sys/kernel/tracing/trace_pipe
 VERSION 20070824

Over and over again, it would trigger a massive leak.