ftrace_set_filter_ips(9)

💅 ftrace_set_filter_ips(9) — Kernel API Manual ✨

okay so bestie, welcome to the ftrace filter-by-addresses page 🎀 this one lives in the Kernel API Manual corner of the world and honestly it's giving "niche but powerful" energy. let's get into it 🫶

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✨ NAME ✨

ftrace_set_filter_ips — set functions to filter on in ftrace by addresses 📍

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🌸 SYNOPSIS 🌸

int ftrace_set_filter_ips (struct ftrace_ops *ops , unsigned long *ips ,
unsigned int cnt , int remove , int reset );

like, that's the whole vibe right there. five args, one int coming back at you 💫

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🦋 ARGUMENTS 🦋

• ops — the ops you're setting the filter with. this is the main character of the whole operation, no cap 👑
• ips — the array of addresses you're adding to (or removing from) the filter. the guest list, basically 📝
• cnt — the number of addresses in ips. gotta tell it how many names are on the list, bestie 🔢
• remove — non zero to remove ips from the filter. like uninviting people from the party 🙈
• reset — non zero to reset all filters before applying this filter. scorched earth, fresh start, periodt 🔥

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💜 DESCRIPTION 💜

So filters denote which functions should be enabled when tracing is enabled ✨ that's the whole point of them.

⚠️ But listen — if the ips array, or any ip specified within it, is NULL, it fails to update the filter. no update, no slay, just failure 😭

And here's the part you cannot skip, bestie: this can allocate memory which must be freed before ops can be freed — either by removing each filtered addr, or by using ftrace_free_filter(ops). 🧹

💀 Memory leak warning fr fr: free it before you free ops. those are your two options and you will pick one of them.

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🌈 SEE ALSO 🌈

Kernel file ./kernel/trace/ftrace.c and honestly the whole extended ftrace cinematic universe 🌌 —

• ftrace_lookup_ip(9)
• ftrace_free_filter(9)
• ftrace_hash_move(9)
• ftrace_location_range(9)
• ftrace_location(9)
• ftrace_text_reserved(9)
• ftrace_bug(9)
• ftrace_update_record(9)
• ftrace_test_record(9)
• ftrace_get_addr_new(9)
• ftrace_get_addr_curr(9)
• ftrace_rec_iter_start(9)
• ftrace_rec_iter_next(9)
• ftrace_rec_iter_record(9)
• ftrace_run_stop_machine(9)
• arch_ftrace_update_code(9)
• ftrace_startup_subops(9)
• ftrace_shutdown_subops(9)
• ftrace_regex_open(9)
• allocate_ftrace_func_mapper(9)
• ftrace_func_mapper_find_ip(9)
• ftrace_func_mapper_add_ip(9)
• ftrace_func_mapper_remove_ip(9)
• free_ftrace_func_mapper(9)
• register_ftrace_direct(9)
• unregister_ftrace_direct(9)
• modify_ftrace_direct_nolock(9)
• modify_ftrace_direct(9)
• hash_add(9)
• update_ftrace_direct_add(9)
• hash_sub(9)
• update_ftrace_direct_del(9)
• update_ftrace_direct_mod(9)
• ftrace_set_filter_ip(9)
• ftrace_ops_set_global_filter(9)
• ftrace_set_filter(9)
• ftrace_set_notrace(9)
• ftrace_set_global_filter(9)
• ftrace_set_global_notrace(9)
• ftrace_ops_get_func(9)
• ftrace_kill(9)
• ftrace_is_dead(9)
• register_ftrace_function(9)
• unregister_ftrace_function(9)
• ftrace_lookup_symbols(9)

like, that's the whole group chat 💬 go read them, iykyk 💅

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okay that's the page!! sourced from ./kernel/trace, dated October 2026, and it goes by ftrace_set_filter_ips(9) — mwah, love that for us 🍓💖 stay filtered, bestie ✨