ignore_event(9)

💖 ignore_event(9) — Kernel API Manual 💖

✨ NAME ✨

ignore_event — Check dereferenced fields while writing to the seq buffer. Bestie, this is the field-safety vibe check for the seq buffer. 👑

🎀 SYNOPSIS 🎀

bool ignore_event (struct trace_iterator *iter );

🌸 ARGUMENTS 🌸

• iter — The iterator that holds the seq buffer and the event being printed. That's the main character carrying both the seq buffer and the event.

💅 DESCRIPTION 💅

At boot up, test_event_printk will flag any event that dereferences a string with "s" that does exist in the ring buffer. It may still be valid, as the string may point to a static string in the kernel rodata that never gets freed. But if the string pointer is pointing to something that was allocated, there's a chance that it can be freed by the time the user reads the trace. This would cause a bad memory access by the kernel and possibly crash the system. 💀

No cap, this function will check if the event has any fields flagged as needing to be checked at runtime and perform those checks.

If it is found that a field is unsafe, it will write into the iter->seq a message stating what was found to be unsafe. So you get the receipts right in the seq buffer. 🧚

🔥 RETURN 🔥

true if the event is unsafe and should be ignored; false otherwise. That's the whole read. 💅

🌈 SEE ALSO 🌈

Kernel file ./kernel/trace/trace.c — plus the whole squad:

• trace_array_put(9)
• tracing_is_enabled(9)
• tracing_on(9)
• tracing_snapshot(9)
• tracing_alloc_snapshot(9)
• tracer_tracing_disable(9)
• tracer_tracing_enable(9)
• tracing_off(9)
• tracer_tracing_is_on(9)
• tracing_is_on(9)
• register_tracer(9)
• tracing_start(9)
• tracing_stop(9)
• trace_buffered_event_enable(9)
• trace_buffered_event_disable(9)
• trace_dump_stack(9)
• trace_adjust_address(9)
• tracing_update_buffers(9)
• trace_user_fault_destroy(9)
• trace_user_fault_init(9)
• trace_user_fault_get(9)
• trace_user_fault_put(9)
• trace_user_fault_read(9)
• err_pos(9)
• tracing_log_err(9)
• trace_array_get_by_name(9)
• tracing_init_dentry(9)

💖 okay that's the page, bestie! From ./kernel/trace · October 2026 · ignore_event(9) — periodt, slay, and may your fields always be safe ✨💅