Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix union collision of module and refcnt for dynamic events In 'struct trace_event_call', the 'module' pointer and the 'refcnt' atomic variable share the same memory space in a union. For dynamic events, the union member is 'refcnt', which acts as an active reference counter. When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or wprobe) has a non-zero reference count (e.g. due to active event triggers or perf attachments), its 'call->module' evaluates to a small non-zero integer instead of NULL. When filtering or setting events for a specific module (e.g., writing ':mod:<module>' to 'set_event'), the code in '__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads 'call->module' directly without checking whether the event is dynamic. This causes the kernel to treat the small integer (refcnt) as a 'struct module' pointer, leading to a NULL/invalid pointer dereference (Oops) when dereferencing the module name. Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked before treating 'call->module' as a valid pointer in these code paths.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 4c86bc531e60900053384867c082675bba82c29f before b6a4575f22925da7e6aa00171e9fc0e5029c0bc9; affected 4c86bc531e60900053384867c082675bba82c29f before 43a23dfe0024afd3d2b0232e987d0292919a9b24; affected 4c86bc531e60900053384867c082675bba82c29f before b4eb07bde606c2096b24252be589e735eff6d413 |
| Linux / Linux | affected 6.14; unaffected 0 before 6.14; unaffected 6.18.42 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.