ftrace_set_notrace(9)

💖 NAME 💖 — ftrace_set_notrace(9) from the Kernel API Manual

okay so bestie, welcome to the ftrace_set_notrace(9) page from the Kernel API Manual. this is literally how to set a function to not trace in ftrace — that’s the NAME, that’s the whole assignment. 💅

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🔥 SYNOPSIS 🔥

the signature is giving:

int ftrace_set_notrace (struct ftrace_ops *ops , unsigned char *buf , int len , int reset );

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🎀 ARGUMENTS 🎀

• ops — the ops to set the notrace filter with. main character of this call, tbh.
• buf — the string that holds the function notrace text. yes, that exact string.
• len — the length of the string. no cap.
• reset — non-zero to reset all filters before applying this filter. that non-zero detail is doing work here.

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🦋 DESCRIPTION 🦋

Notrace Filters denote which functions should not be enabled when tracing is enabled. they’re the “do not trace these” list, okay? 🙈

if buf is NULL and reset is set, all functions will be enabled for tracing. that’s the reset-all-the-notrace-vibes situation, bestie.

💀 technical caveat time, and please don’t skip it: 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). like, the cleanup is not optional. the ops does not get to be freed until that memory is handled. periodt.

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🌈 SEE ALSO 🌈

Kernel file ./kernel/trace/ftrace.c — start there, iykyk.

• 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_set_filter_ips(9), ftrace_ops_set_global_filter(9)
• ftrace_set_filter(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)

xoxo, your Kernel API Manual bestie — source ./kernel/trace, October 2026, all about ftrace_set_notrace(9) 🫶✨