tracing_log_err(9)

🎀 tracing_log_err(9) — the Kernel API Manual, but make it bestie 💅

okay so welcome to the tracing_log_err(9) page, from the Kernel API Manual ✨ this one's short and sweet and honestly kinda iconic — it's all about dropping an error into the tracing error log 🫶

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✨ NAME ✨

tracing_log_err — write an error to the tracing error log 📝🔥

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💖 SYNOPSIS 💖

void tracing_log_err (struct trace_array *tr , const char *loc , const
char *cmd , const char **errs , u8 type , u16 pos );

like yes bestie, that's the whole signature, no cap — copy it exactly, do not come for my formatting 😭

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🌸 ARGUMENTS 🌸

• tr — the associated trace array for the error, and yes it takes NULL for the top level array 👑
• loc — a string describing where the error occurred, like the little "we were here" sign 📍
• cmd — the tracing command that caused the error, the actual culprit fr fr 💀
• errs — the array of loc-specific static error strings 🧚
• type — the index into errs[], and that's what produces the specific static err string ✨
• pos — the position the caret should be placed in the cmd 🎯

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🦋 DESCRIPTION 🦋

so it writes an error into tracing/error_log of the form:

<loc>: error: <text> Command: <cmd> ^

that caret at the end? that's the pos doing its little main character moment, pointing right at the problem 💅

tracing/error_log is a small log file containing the last TRACING_LOG_ERRS_MAX errors (that's 8, bestie — eight whole errors, a whole little squad 🌈). Memory for errors isn't allocated unless there has been a tracing error — so it's lowkey chill and doesn't hog memory for no reason 🫶. and the error log can be cleared and have its memory freed by writing the empty string in truncation mode to it, i.e.:

echo > tracing/error_log

that's it, that's the cleanse 🧖‍♀️✨

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💜 NOTE 💜

okay this part matters, listen up 🙈 — the errs array along with the type param are used to produce a static error string. this string is not copied and saved when the error is logged — only a pointer to it is saved 👀. so like, pointer vibes, not copy vibes. see existing callers for examples of how static strings are typically defined for use with tracing_log_err 🎀

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⭐ SEE ALSO ⭐

Kernel file ./kernel/trace/trace.c — and here's the whole crew, no one left behind 💖:

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), ignore_event(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), trace_array_get_by_name(9), tracing_init_dentry(9)

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and that's the page!! 💐 this came from ./kernel/trace, dated October 2026, and the manual page itself is tracing_log_err(9) — okay love u, go log those errors responsibly 🫶💅✨