CVE-2026-97443
perf/ftrace: Fix WARNING in __unregister_ftrace_function
Description
In the Linux kernel, the following vulnerability has been resolved: perf/ftrace: Fix WARNING in __unregister_ftrace_function perf_ftrace_function_unregister() unconditionally calls unregister_ftrace_function() without checking whether the ftrace_ops was ever successfully registered. This triggers a WARN_ON in __unregister_ftrace_function() when the ops doesn't have FTRACE_OPS_FL_ENABLED set. This can happen during perf_event_alloc() error cleanup when perf_trace_destroy() is called via __free_event() on an event whose ftrace_ops registration failed or was already torn down by perf_try_init_event()'s err_destroy path. The call path is: perf_event_alloc() error cleanup -> __free_event() -> event->destroy() [tp_perf_event_destroy] -> perf_trace_destroy() -> perf_trace_event_close() -> TRACE_REG_PERF_CLOSE -> perf_ftrace_function_unregister() -> unregister_ftrace_function() -> __unregister_ftrace_function() -> WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)) Fix this by checking FTRACE_OPS_FL_ENABLED before attempting to unregister. If the ops is not enabled, just free the filter and return success.
INFO
Published Date :
Sept. 24, 2026, 5:17 p.m.
Last Modified :
Sept. 25, 2026, 1:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest version.
- Apply the provided patch for perf/ftrace.
- Verify ftrace function registration before unregistering.
- Free the filter if the ops is not enabled.
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CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-97443 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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approaches employed by adversaries to exploit the CVE-2026-97443
weaknesses.
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The following table lists the changes that have been made to the
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 25, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/97xxx/CVE-2026-97443.json">CVE-2026-97443</a> -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 24, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: perf/ftrace: Fix WARNING in __unregister_ftrace_function perf_ftrace_function_unregister() unconditionally calls unregister_ftrace_function() without checking whether the ftrace_ops was ever successfully registered. This triggers a WARN_ON in __unregister_ftrace_function() when the ops doesn't have FTRACE_OPS_FL_ENABLED set. This can happen during perf_event_alloc() error cleanup when perf_trace_destroy() is called via __free_event() on an event whose ftrace_ops registration failed or was already torn down by perf_try_init_event()'s err_destroy path. The call path is: perf_event_alloc() error cleanup -> __free_event() -> event->destroy() [tp_perf_event_destroy] -> perf_trace_destroy() -> perf_trace_event_close() -> TRACE_REG_PERF_CLOSE -> perf_ftrace_function_unregister() -> unregister_ftrace_function() -> __unregister_ftrace_function() -> WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)) Fix this by checking FTRACE_OPS_FL_ENABLED before attempting to unregister. If the ops is not enabled, just free the filter and return success. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/97xxx/CVE-2026-97443.json">CVE-2026-97443</a> Added Reference https://git.kernel.org/stable/c/7f845820afaad339341c2ae42bc7fdec175df9ea Added Reference https://git.kernel.org/stable/c/9581123304b23049437324038698af9fb56ee663 Added Reference https://git.kernel.org/stable/c/df097713b56ffac5eed32a9be2e7d27ac48d9087