Re: [PATCH v2 1/2] tracing: Add the bucket size to expr_field_str()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Incorrect format specifier `%ld` for `unsigned long` field `buckets`.
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commit d2b0e0ac39deb1a14a5fe6656a43dc160480944d
Author: Donggeun Yoo <donggeunyoo.kernel@gmail.com>

tracing: Add the bucket size to expr_field_str()

This commit updates expr_field_str() to append the bucket size count to the
rendered string. This matches the behavior of hist_field_print() and allows
legal histogram keys with .buckets to be handled correctly.

> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 963e0d6b61fdf..9d7ce01fda360 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -1755,6 +1755,9 @@ static bool expr_field_str(struct hist_field *field, struct seq_buf *s)
>  			seq_buf_printf(s, ".%s", flags_str);
>  	}
>  
> +	if (field->buckets)
> +		seq_buf_printf(s, "=%ld", field->buckets);

[Severity: Low]
Since field->buckets is an unsigned long, could formatting it with %ld
cause it to print as a negative number if the highest bit is set?

If a user configures a histogram trigger specifying a .buckets size that
exceeds the maximum signed long value, it appears the field will incorrectly
print with a negative bucket size (e.g., =-9223372036854775808) when the
configuration is read back through tracefs.

Would %lu be more appropriate here?

> +
>  	return !seq_buf_has_overflowed(s);
>  }

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Sashiko AI review · https://sashiko.dev/#/patchset/20260913203129.941270-1-donggeunyoo.kernel@gmail.com?part=1